Labor leader Bill Shorten has raised concerns over elements of the government's proposed data retention bill.
In a letter to Prime Minister Tony Abbott, the opposition leader said that he supports the "expeditious consideration" of the government's Telecommunications (Interception and Access) Amendment (Data Retention) Bill 2014, once the current parliamentary inquiry into the bill has completed its work and "any necessary amendments have been drafted and circulated for consideration by Senators and Members".
However, the letter, published by Fairfax, raises concerns about the cost of the regime, press freedom, and the decision to define the data covered by the regime in regulation rather than legislation.
Abbott last month wrote to the opposition leader asking for bipartisan support to push the bill through parliament in the week starting 16 March.
The prime minister wrote that security agencies "are going blind as telecommunications providers retain less data for less time."
The PM told a press conference earlier this month that he wanted the legislation to implement the scheme passed "as quickly as is humanly possible".
In his letter to Abbott, dated 9 February, Shorten wrote that it is "essential" that information on the costs of the data retention regime be released before parliament debates the bill.
"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," the letter states.
The government has engaged PricewaterhouseCoopers to assess the cost of implementing the scheme. However, the Parliamentary Joint Committee on Intelligence and Security, which is conducting the inquiry into the bill, has so far not been provided with any of PwC's findings.
The PJCIS is due to report on the data retention bill at the end of the month.
The Attorney-General's Department told a hearing of the inquiry earlier this month that there were as yet no plans to provide the committee with any of the material produced by PwC.
Shorten said that estimates of the aggregate cost of the regime formulated by the Data Retention Implementation Working Group, which brings together government and industry representatives, based on PwC's work, should be made available.
The government has previously indicated it will make a contribution to the setup cost incurred by telcos covered by the scheme.
Shorten's letter notes the concerns expressed by media organisations over the impact of the bill on press freedom and states that "Press freedom concerns about mandatory data retention would ideally be addressed in this Bill to avoid the need for additional amendments or procedures to be put in place in the future".
The letter also notes the objection from many of the bill's critics to the data set being defined in regulation.
The bill as it stands sets out only general categories of data that telecommunications providers will be forced to retain.
"Officials from the Attorney-General's Department confirmed at public hearings of the PJCIS that the regulation describing the proposed data set can be produced for the Committee, and I would ask that you ensure that this occur immediately to enable appropriate scrutiny," the letter states.
"The Bill proposes that the data set be defined by regulation, however other submitters have argued strongly that as a matter of transparency and accountability the data set should be included in the Bill itself. This will be a further important matter for the PJCIS to consider."
"I am advised that representatives of Australia's three largest telecommunications providers, Telstra, Optus and Vodafone, which carry the vast majority of Australia's telecommunications, all confirmed at the PJCIS hearings that none of them has any plan to reduce the amount of data they presently retain," the letter states.
"I appreciate that the purpose of the Bill is to meet the identified risk that in the future less data may be retained by telecommunications providers, but I note that the Bill itself does not immediately impose new retention obligations. Rather, the Bill requires progressive compliance over a period of up to two years."
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