Attorney-General George Brandis has cited police use of metadata in a nationally high profile murder prosecution to illustrate why the government wants to push ahead with new data retention laws.
The government has unveiled plans for telecommunications companies to retain two years of metadata records in a move designed to assist police and counter-terrorism agencies combat what they argue is a growing terrorist threat.
Metadata includes the phone number from which a call is made, the number to which it is made, the identity of the owners of those numbers, the location of the caller and the recipient and the time and duration of a call.
Earlier on Wednesday, Prime Minister Tony Abbott was forced to clarify details of his government's contentious plans to store people's phone and internet logs after he initially suggested that a person's web browser history would be stored.
Metadata also includes the internet protocol address of a website visited but not which web pages have been visited on a given website.
Mr Abbott later confirmed internet service providers were only being asked to store metadata, likening the information to that included on the ''front of an envelope'' but not the contents of the letter.
Senator Brandis later appeared to contradict Mr Abbott when, in an interview on Sky News, he said what would be captured under the government's proposed changes was ''the web address. The electronic address of the website''.
''What you are viewing on the internet is not what we are interested in … what the security agencies want to know, to be retained, is the electronic address of the website,'' he said.
The primary focus of the new laws was combating terrorism, Senator Brandis said, ''but the fact is that access to metadata is an extremely useful investigative tool''.
Access to metadata assisted police in successfully prosecuting the killer in the high profile case, he said. Fairfax Media cannot identify the case due to a legal order.
Internet service providers have warned of additional costs - or a so-called surveillance tax - under the push for uniform data retention laws that could see them pass the costs on to consumers.
Government officials said they were still in discussions with internet service providers - some of whom do not currently hold two years of metadata - about the potential additional costs they could face, but admitted ISPs could face an additional impost.
The officials stressed that agencies could not look at web-surfing histories without a warrant.
Labor leader Bill Shorten said the opposition welcomed a debate on bringing national security laws up to date but said the ALP was concerned ''that when you store so much information about so many Australians that this needs to be done very carefully''.
''We are concerned that the government is going to ask the internet providers to pay for these measures which will see a new internet tax on all Australians. We are also concerned to be very careful that there is no risk that ordinary Australians are being treated as if they are criminals.''
ASIO boss David Irvine has described metadata retention as ''absolutely crucial'' in monitoring and disrupting local terror cells.
The story Government wants telcos to keep two years of metadata first appeared on The Sydney Morning Herald.