iiNet told the committee in September that a data retention scheme could to set up and that it would pass on the cost to customers, which would equate to around $5 extra per month.

The Communications Alliance and Australian Mobile Telecommunications Association have also estimated data retention could .

Ruddock warned the AGD that it would need to consider the cost of any data retention scheme.

"We haven't got any quantification, although we could probably do that on the basis of what happens currently. A cost sharing arrangement has the benefit of concentrating everybody's mind on making sure that it's as efficient as possible..." Roger Wilkins said, secretary at the AGD.

"I'm not sure in the time available we'll be able to make submissions around that type of cost, but cost has been a consideration."