The Law Council of Australia has come out swinging against the government's proposed mandatory data retention regime, describing it as not "reasonable, necessary and proportionate".

The policy opposing the Telecommunications (Interception and Access) Amendment (Data Retention) Bill 2014 was adopted on 29 November.

"The Law Council accepts that there is a legitimate need for law enforcement and intelligence agencies to have access to telecommunications data in the possession of telecommunication and internet service providers, for the purpose of carrying out their statutory functions," the policy states.

However the policy says that the Law Council does not support a mandatory data retention regime because:

a. the purpose of mandatory data retention is unclear;

b. blanket mandatory data retention has not been demonstrated as reasonable, necessary or proportionate by the government;

c. the government should explore less restrictive alternatives that will meet legitimate counter-terrorism purposes;

d. the nature and scope of the data to be retained is unclear, uncertain and subject to change by the Executive; and

e. it does not provide safeguards or restrictions for civil or for non-law enforcement purposes.

"Any mandatory data retention scheme must be shown by the government to be reasonable, necessary and proportionate to a legitimate purpose," the organisation's president, Michael Colbran QC, said in a statement.

"It appears that under the proposed data retention scheme, more and additional kinds of telecommunications data will be available – both in terms of volume and potentially the quality of the data retained – than is currently the case.

"This change heightens the potential for privacy issues to arise because of the nature and scale of the telecommunications data that will be retained and able to be interrogated at a later time."

If a data retention regime is introduced safeguards should be put in place, include a warrant process and oversight mechanisms.

The Law Council backs the introduction of warrants for law enforcement agencies that want to obtain so-called metadata from telecommunications providers.

"Telecommunications data can reveal various pieces of personal information about an individual – for example, revealing who a person contacts, how often and where," Colbran said.

“A warrant should be required to access personal information to ensure that it is only accessed where it is really necessary for the purpose of preventing or detecting serious crime or threats to national security."

"The Law Council considers it is necessary to retain the existing warrant process for content, but to also require a warrant for obtaining access to telecommunications data," the policy states.

"A warrant is required because under the proposed data retention regime, vastly more telecommunications data will be available – both in terms of volume and potentially the quality of the data retained – than is currently the case. The change heightens the potential for privacy issues to arise because of the nature and scale of the telecommunications data that will be available. There is also greater potential impact on client legal privilege in circumstances when telecommunications data can be obtained about when, where and how often a client seeks legal advice."

The government's bill is currently the subject of an inquiry by the Parliamentary Joint Committee on Intelligence and Security. The committee is due to report by 27 February 2015.