Mr Thodey's comments came after Telstra and two other telcos met Communications Minister Malcolm Turnbull and Attorney-General George Brandis last week to discuss the government's data retention proposal, which would require them to store their customers' metadata for law-enforcement agencies. The comments are in stark contrast to those by Steve Dalby, the outspoken chief regulatory officer at iiNet, and to a leaked internal Optus memo last week. Mr Dalby said the retention scheme would amount to a "surveillance tax" of up to $10 a month that iiNet would have to pass on to subscribers if it had to bear the cost of retaining the data. The amount was based on confidential briefings iiNet held with government officials in 2010. Mr Dalby said it would cost between $60 million and $100 million a year to retain the data required, with the cost increasing as more data was collected. Optus said in an internal memo, cited by The Australian Financial Review, that it should not have to bear the costs of the government's plan.

"Based on work done in 2010 and refreshed in 2012, a data retention regime could cost Optus in the order of $30-plus million to $200-plus million, depending on a range of assumptions about scope and definition," the memo said. Optus also said despite what ministers and agencies had said, it did not always keep the data agencies were after. "Arguments to the effect that we 'keep this data anyway' do not prevail to the extent that inadequate recognition is given to the true cost and business impact," it said. On a landline or mobile telephone, metadata includes your number, who you called, what time you made the call, the duration of the call, and location from which you made the call. What the government understands to constitute metadata on the internet remains unclear. While Prime Minister Tony Abbott and Senator Brandis said last week it would include web browsing histories, Mr Turnbull ruled this out, saying it would instead include the IP address assigned to you when you were using the internet.

But Geoff Huston, a veteran telecommunications expert and one of the people credited with bringing the internet to Australia, has argued that to store such information would also require destination IP addresses, that is of websites visited, to be retained. Mr Huston, now chief scientist at the Asia Pacific Network Information Centre (APNIC), said that destination addresses and other information would need to be stored because, in today's world, many consumer, business and university connections shared the same IP address. . He added that, without storing the destination address data, it would be nearly impossible to identify those using shared IP addresses. Australian agencies accessed metadata 330,640 times during criminal and financial investigations in 2012-13 - an 11 per cent increase in a year and a jump of 31 per cent over two years. It is unclearwhether the figure is a true representation of the number of Australian citizens who had their metadata accessed, as the Attorney-General's department has yet to clarify whether one request includes access to multiple peoples' metadata.