Attorney-General George Brandis has revealed that a secretive report into the cost of the Government's proposed data retention scheme put the ongoing financial burden on telcos at just under $4 per customer per year.
PricewaterhouseCoopers was last October hired by the Attorney-General's Department to estimate how much the telecommunications industry would need to spend in order to meet its obligations under the retention regime.
While telcos such as iiNet and Optus have placed the cost of implementing the scheme in the hundreds of millions - with ongoing costs of at least $100 million in future years - the Government has so far declined to publish the findings from the PwC report.
Brandis has as yet only been willing to detail PwC's estimated costs for the implementation of the scheme, which the consultancy firm put at between $188.8 million and $319.1 million.
The Attorney-General has consistently cited cabinet-in-confidence in response to calls to publicly release the report's full findings.
However, during debate in the Senate on the data retention bill last night, Brandis gave further insight into PwC's figures.
He said the firm's review had estimated that the average cost - taking any Government contribution out of the equation - of the scheme over ten years would equate to between $1.83 and $6.12 per customer per annum.
The estimate equated to a median figure of $3.98 per customer per annum, Brandis said.
"That is not .. it seems to me, a vast cost," he said.
The estimate indicates that for Australia's largest telco Telstra alone - which locally provides around 16 million retail mobile services, 7.5 million fixed voice services and 3.7 million fixed data services - the average cost of the scheme could sit around $95 million a year over the next 10 years.
Tthe Communications Alliance has estimated the scheme would cost the industry $319 million to set up.
Telcos and internet service providers have previously said costs arising from the scheme would need to be passed on to consumers as part of their monthly bill.
Brandis made his comments in response to questions around the Government's promised - but as yet undetailed - "substantial" financial contribution to the set-up of the scheme.
The Attorney-General once again declined to provide a figure for the Government's contribution, saying it would be revealed as part of the 2015 Budget process.
Last week 16 chief executives of Australia's top phone and internet providers united to demand Brandis and the Government come clean on the Government's planned contribution to the scheme.
The CEOs - from the likes of Telstra, Optus, Vodafone, M2, iiNet, Macquarie Telecom and others - urged the Government to provide certainty on both the size of the funding allocation and how it would be distributed between the industry players.
They argued the industry needed clarity to allow carriers and ISPs to work out how much they would need to spend on the scheme and how much they would have to pass on to customers.