Australia’s law-enforcement agencies are sidestepping the courts to obtain the vast majority of their phone-tap and email interception warrants from the Administrative Appeals Tribunal (AAT) – a body that has attracted criticism for the number of its political appointees, some without legal qualifications.

Figures from the Home Affairs Department show more than three-quarters of the 3524 interception warrants that state and federal police and anti-corruption bodies obtained in a year were authorised by members of the AAT, not by judges.

In 2017-18 – the most recent year for which figures are available – the AAT signed off on 2735 interception warrant applications from 17 agencies nationally, or 78 per cent, according to the annual report on the operations of the Telecommunications (Interception and Access) Act.

Among the three other warrant-issuing authorities, Federal Circuit Court judges approved 445 interception warrants, Family Court judges 335 and Federal Court judges just nine.

Between them, the four agencies refused five applications during that period – three from New South Wales Police, one from the Northern Territory Police and one from Victoria’s Independent Broad-based Anti-corruption Commission.

Information obtained through the warrants was used in 5415 prosecutions and 3516 convictions.

Separately, the report said 20 law-enforcement agencies also made 301,113 authorisations for disclosing historical telecommunications data – a rise of 889 on the previous year.

NSW Police most favoured applying to the AAT for interception warrants, obtaining 1338 that way in 2017-18, compared with 71 through the Federal Circuit Court and just one through the Federal Court.

The Australian Federal Police (AFP) also obtained most of their approved interception warrants through the AAT – 642 compared with 51 through the Federal Circuit Court, 29 through the Family Court and two through the Federal Court.

Only 39 members of the AAT are authorised to issue warrants. They are required under legislation to be currently enrolled as legal practitioners in the Federal or High courts or the Supreme Court of any state or territory and to have been enrolled as such for at least five years.

An AAT spokesperson said: “A small number of AAT members are authorised or nominated under a range of acts to issue warrants or exercise other powers in their personal capacity at the request of federal and state bodies.”

Some legal experts argue that judges are more experienced and therefore more qualified to assess warrant applications than a lawyer with five years’ practising experience. Key to this is the fact that during these warrant proceedings, there is no party making an opposing argument.

The Saturday Paper asked various agencies why they chose the AAT over other authorities. Some suggested the skew towards the AAT simply reflected the availability of the various authorities to hear warrant applications, with some AAT members more accessible at short notice than a judge.

What is not clear is whether AAT members are also considered more likely to readily approve the applications than judges.

The AFP said in a statement that the legislation permitted all four authorities to issue warrants.

“All authorising officers must give the same due consideration to information put before them regardless of the office they hold in determining whether to issue a warrant. In accordance with the legislation, the AFP does not preference any particular officer holders in seeking the issue of a warrant,” it said.

NSW Police said it did not comment on operational methodology.

“However, all warrant applications relating to telephone interception must comply with legislative requirements,” its statement said.

“The constitution and oversight of the tribunal no longer promotes public trust and confidence in the decision-making and that is an objective of the act,” Rex Patrick told The Saturday Paper.

A spokesman for Queensland Police, which applied to the AAT less frequently, said: “The decision to make an appointment before a Federal Circuit Court judge or an Administrative Appeals Tribunal member is often impacted by availability and suitability of appointment time.”

The Home Affairs Department report on interception warrants was tabled in parliament last week, the same day that Attorney-General Christian Porter made public the findings of a government-commissioned review of the AAT by former High Court judge Ian Callinan.

Traditionally, the AAT’s job is to review administrative decisions made by government departments and agencies, examining the facts in each case in relation to the law and government policy and determining if decisions should be varied, set aside or affirmed.

But select members in its general division also have a role in approving applications from state and federal police forces, anti-corruption bodies and other law-enforcement agencies for interception and surveillance warrants in criminal and other investigations.

Another Home Affairs Department annual report on warrants issued under the Surveillance Devices Act 2004 does not specify how many of those warrants the AAT also issued.

The Australian Security Intelligence Organisation’s warrant applications are handled separately. The tribunal’s security division is responsible for those.

In recent years, the AAT’s workload has increased dramatically, especially since it absorbed the operations of the migration and refugee review tribunals.

Callinan recommended 37 changes to the way the AAT operates. Central among them was that all AAT members should have formal legal qualifications.

Section 7(3)(b) of the Administrative Appeals Tribunal Act allows for the appointment of non-lawyers where they have “special knowledge or skills” that are relevant to the tribunal’s duties.

Some of those whom successive governments have appointed under that provision include former politicians, as well as unionists and political staff, attracting criticism that the tribunal has become politicised.

Attorney-General Porter insists all appointments are made on merit.

Some appointees with party affiliations also have legal qualifications, blurring the lines between merit-based and political appointments.

Justice Callinan also identified another potential compromise of the AAT’s separation from government.

In 2015, the Coalition government abolished the Administrative Review Council (ARC), which had been the scrutineer of AAT decisions since 1976.

In the past four years, the Attorney-General’s Department (AGD) has played that role instead – the same department whose minister appoints the members of the AAT.

Callinan singled out this arrangement for further criticism, saying the Administrative Appeals Tribunal Act assumes the review council’s existence.

“It is in my view contrary to the intention and spirit of that Act that any section of any department of government might have a role of overseeing or inquiring into the work of the AAT, that is the reviewer of decisions made by officials of many other departments of government,” wrote Callinan in his report.

He noted that the ARC had been established to protect the rights of citizens and he was scathing of the circularity of the post-2015 arrangement.

“Its effect is that public servants (in the AGD) would have the role of overseeing the AAT, whose purpose and role is to review the decisions of public servants,” he said.

Several respected figures in the legal and judicial community told The Saturday Paper they have concerns about the extent of the AAT’s involvement in the issuing of interception warrants.

The president of the Law Council of Australia, Arthur Moses, said the way appointments were made was crucial to the public perception of independence.

“If the AAT is to issue these types of warrants, then there needs to be an independent and transparent appointments process to shield AAT members from perceptions of bias,” Moses told The Saturday Paper. “This will help ensure the public confidence in the AAT is not undermined.”

Eminent lawyer and former independent national security legislation monitor Bret Walker, SC, said that AAT members differed from judges, including by virtue of the duration of their appointments.

Walker told The Saturday Paper that limited-tenure tribunal positions carrying the possibility of reappointment made their recipients naturally less independent of the appointing government than judges.

“The expediency of using the AAT as a warrant-issuing authority is institutionally inferior to the established traditional notion of using the judiciary,” said Walker.

“[This is] because, put simply, the AAT does not have the institutional separation from the executive that comes from the one-off appointment and the judicial tenure that the judiciary has.”

Former Victorian Supreme Court judge David Harper holds a similar view.

“Judges have the great benefit in their decision-making of being absolutely independent of government,” Harper told The Saturday Paper.

“The independence of members of tribunals is not absolute in the sense that they are appointed for fixed terms. And if a member of such a body wishes to be reappointed, then the temptation to act in ways that would facilitate that reappointment, even if not front of mind, may have some influence – some influence – on the decisions that that member makes.”

Harper is among a group of six former judges concerned with integrity across government. Facilitated by progressive think tank The Australia Institute, the group has formed what it calls a “national integrity committee” to examine and raise integrity-related issues, particularly the lack of a national anti-corruption commission.

David Harper joined crossbench MPs and senators at Parliament House on Wednesday to repeat calls for a national integrity commission in the wake of allegations that casino giant Crown may have circumvented the visa system to bring in so-called high-roller gamblers from China, some of whom may have engaged in criminal behaviour.

Crown has strenuously denied the allegations and called them an attempt at “smear”.

Independent Sydney-based MP Zali Steggall, a former lawyer, emphasised the importance of appropriate legal qualifications in quasi-judicial positions – particularly in relation to a proposed national integrity commission.

“An integrity commission allows the proper investigation of allegations, and so there’s a testing of the evidence, there’s a hearing of testimony and there’s a proper assessment,” said Steggall.

“So it doesn’t become a trial by media, it doesn’t become a Star Chamber. It actually becomes a process by which serious allegations that are extremely important to the Australian public can be properly investigated by people of appropriate training and legal expertise and independence.”

Christian Porter said on Thursday that a draft bill to establish a Commonwealth integrity commission was being finalised and would be completed by year’s end.

A crossbench attempt to force the house of representatives to establish a standing committee to examine the Crown Casino allegations was defeated 127 to five, when the Coalition and Labor voted together to oppose it.

Instead, Porter announced that the Australian Commission for Law Enforcement Integrity (ACLEI) would examine the allegations.

“A strong integrity and professional standards culture is fundamental to public confidence in our work and the Australian government’s work,” Porter said on Tuesday.

ACLEI is one of the law-enforcement bodies able to apply to the AAT for interception warrants. In 2017-18, it obtained six such warrants through the Federal Circuit Court and 10 through the AAT.

Centre Alliance senator Rex Patrick said there was a need for better transparency to instil confidence in the quasi-judicial system. He suggested the AAT was at risk of wandering from its remit as spelt out in the Administrative Appeals Tribunal Act.

“The constitution and oversight of the tribunal no longer promotes public trust and confidence in the decision-making and that is an objective of the act,” Patrick told The Saturday Paper.

Patrick put a motion to the senate on Thursday calling for the repeal of section 7(3)(b) that allows non-lawyers to be appointed. The motion was defeated when the Coalition and Labor voted against it.

Successive governments have appointed former politicians, political staff and other party affiliates to the tribunal, some of whom were legally qualified and some of whom were not.

In his review of the AAT, Callinan criticised what he suggested was the practice of some in the tribunal of handing off the task of drafting tribunal decisions to clerical staff. Although some of those staff have legal qualifications, Callinan said it was the job of the tribunal members to write the decisions, not their assistants.

Callinan also singled out the migration and refugee division for special criticism, saying it was not keeping up with its workload.

He said some members of the AAT who handled migration and refugee decisions were sometimes acting “adversarially” instead of “inquisitorially”.

He recommended that particularly in the migration and refugee division and the social security and child support division, counsel assisting should be appointed.

Porter has not yet formally responded to Callinan’s report, which he received in December last year and made public last week.

On February 21, two months after receiving it and just under three months before the federal election, the attorney-general announced 86 appointments to the AAT – 34 new and 52 reappointments.

AAT members’ appointments are for three, five or seven years.

The clutch of appointments announced in February included Joe Francis, a former WA Liberal government minister, and Shane Evans, a former adviser to the federal Howard and NSW O’Farrell Coalition governments. Both were appointed to seven-year terms.

Other appointees were Queensland Liberal National Party adviser Dr Dominic Katter, and Phoebe Dunn, who served as an adviser to ministers in successive Victorian Liberal governments and to then foreign minister Alexander Downer.

Part-time appointees included former senate president Stephen Parry, who lost his seat in parliament after being found ineligible under section 44 of the constitution, due to dual citizenship. Former federal Liberal MP Bob Baldwin, former federal Nationals MP De-Anne Kelly and former Liberal adviser Tony Barry were also among those appointed to serve part-time.

Porter also appointed a former Labor MP, David Cox. Another former Labor MP and former federal attorney-general, Duncan Kerr, was previously president of the AAT.

In his review of the AAT, Callinan issued what amounted to a rebuke of tribunal members for handing off other aspects of their work to registry staff, including holding mediation conferences that he said should be undertaken by properly qualified members only.

He said the registry staff should not be giving “legal advice” to members or helping them prepare their written decisions.

“The expectation of the community is, surely, that the whole of the decision-making process is undertaken by the Members and not staff of the public service, however well-intentioned that staff may be,” he said.

He criticised the use of the title “associate” for employees who were clerical assistants.

“The term ‘Associate’ that Members of the General and other Divisions tend to use for their assistants is an unnecessarily grand title for the largely clerical job to be done and which should be done at low cost to the public,” Callinan said, recommending they be called “clerk assistants” instead.

He said requests from members to registry staff should be restricted to retrieving material from the library and anything resembling advice or drafting was “not acceptable”.

Callinan was alarmed that the registry had hired an external consultant to perform what should have been routine administration, at an unspecified cost.

He said registry staff should not have been spending money on travel, meetings and other discussions as part of what they called a “registry transformation program” on the eve of his review.

A spokesman for the attorney-general said the Callinan review was published within the statutory time limit of 15 parliamentary sitting days and that February’s appointments had all been well advanced when it was received.

He referred The Saturday Paper to the attorney’s previous comments.

When the appointments were announced in February, shadow attorney-general Mark Dreyfus accused Porter of politicising the tribunal.

Porter responded that Labor had regularly appointed people with connections to the Labor Party.

“Indeed there is nothing wrong with that, so long as the candidates are well qualified, which very often is the case with respect to people who have been involved in politics and public administration,” said Porter.

“Indeed, our government has appointed several notable former Labor politicians to the AAT because they are qualified for the role.”

He said he had been particularly focused on appointing candidates that were likely to reflect “community values”.

Porter’s spokesman reiterated that all appointments were made on merit.