The letter, obtained by Fairfax Media, comes despite reports last week Tony Abbott Credit:AP If passed in its current form, the bill would require Australian internet and phone companies, such as Telstra, Optus, Vodafone and iiNet, to store for two years customer "metadata" for warrantless access by law-enforcement and intelligence agencies to fight crime and terrorism. Data retained about phone calls under the scheme would include who you have called, who has called you, the start and finish time of the call, and the duration – but not the contents. The IP address allocated to your internet connection would also be stored so that agencies can trace back those who breach laws online. Civil liberties and privacy groups have largely said that the scheme is not needed and would amount to mass surveillance on the population. Meanwhile, law-enforcement and intelligence agencies say access to metadata is "crucial" and that they will go blind without data retention.

While telcos are not presently required to store metadata, they are required to hand over to authorised agencies that request it any metadata they have, without any judicial oversight. In the last financial year, metadata was disclosed more than half a million times. "I am disappointed that recent media briefing has sought to politicise the development and consideration of anti-terrorism legislation," Mr Shorten wrote to Mr Abbott in a letter dated February 9. "This is at odds with a responsible and bipartisan approach to such important issues." Mr Shorten's letter to Mr Abbott follows one sent by the Prime Minister to Mr Shorten, subsequently leaked to The Australian, in an apparent attempt to put pressure on Labor to pass the third tranche of national security laws in an expedited timeframe. Mr Abbott's letter, dated January 22, urged Labor to support the data retention bill and requested that it be passed by Parliament no later than March 26, which is just 38 days away.

In his letter, Mr Abbott spoke of how he had "reluctantly" agreed to delay introducing the legislation for debate until after the powerful Parliamentary Joint Committee on Intelligence and Security (PJCIS) reported on the new laws on February 27. But Mr Shorten said a number of issues remained that required considered parliamentary oversight. "In the hundreds of submissions received by the PJCIS, and at the public hearings of the committee, a number of significant matters and concerns regarding the bill have been brought to the attention of the committee," Mr Shorten wrote. PJCIS committee members are currently debating what recommendations, if any, to include in their report to government. If the Coalition-dominated committee can't agree on unanimous recommendations, there could be a dissenting minority report from Labor. The PJCIS hasn't had a dissenting minority report since at least 2006, when it was reviewing the listing of the Kurdistan Workers Party (PKK) as a terrorist organisation.

Costs Among the issues with the data retention scheme, Mr Shorten outlined in his letter how the costs of it were still unknown. Also unknown was how much money the government was willing to pour into it and how much money the industry would have to bear as well as the Australian public if costs were passed on. "Although the costs of the scheme to individual service providers may be commercial in confidence, no such claim can be made about the aggregate cost of the scheme to the Australian community," Mr Shorten wrote. In October last year, the Attorney-General's Department commissioned Pricewaterhouse Coopers to estimate the total cost of setting up a data retention scheme. To date, the government has argued that it can't be released because it relates to cabinet deliberations and contains confidential information. Despite this, Fairfax Media understands the government is considering releasing the aggregate figure soon. It's understood it will say the costs will be anywhere between $100 million and $300 million.

Mr Shorten said the bill should not be debated until costs were made public. "It would be unreasonable to expect Parliament to debate the bill without senators and members being aware of the cost of the legislation to the Australian taxpayer and the impact on industry," Mr Shorten wrote. Communications Minister Malcolm Turnbull has previously stated that the government expected "to make a substantial contribution to both the cost of implementation and the operation of this scheme", but has not put a number on the exact figure. Mr Turnbull introduced the bill into Parliament last year after he appeared to take over public commentary of it from Attorney-General George Brandis following the attorney's disastrous explanation of metadata. Press freedom

Mr Shorten also expressed concern in his letter about the lack of protection for journalists when it came to having their phone records and internet data accessed during leak investigations. While noting a joint submission provided to the PJCIS on behalf of a number media organisations including Fairfax Media, Mr Shorten said concerns about the erosion of press freedom should "ideally be addressed in this bill to avoid the need for additional amendments or procedures to be put in place in the future". The media organisations' submission outlined concerns that the bill did not include sufficient checks and as a consequence may erode freedom of the press, Mr Shorten said. Final data set Mr Shorten also said the government should "immediately" release the data set so that the PJCIS, telcos and the general public were aware of what data would be stored under the regime.

Although the government has released what it calls a draft data set, it has not been finalised. Mr Shorten also raised objections previously brought up in public PJCIS hearings, which noted that the data set could be changed at any time because it is part of the "regulations" of the bill, which can be changed by the attorney-general of the day without parliamentary oversight. "The bill proposes that the data set be defined by regulation, however other submitters have argued strongly that as a matter of of transparency and accountability the data set should be included in the bill itself," Mr Shorten said. "This will be a further important matter for the PJCIS to consider."