The government needs to spell out exactly what internet data it wants stored for spies and law enforcement agencies so it can “explain and justify” it, Communications Minister Malcolm Turnbull says.

Speaking on Bloomberg TV in the face of criticism the government has demonstrated a lack of understanding of its own proposals, particularly whether the storage of "metadata" would include users' browser history, Mr Turnbull has stressed the policy is still in the consultation and design phase.

“Metadata means different things to different people so what we have to do is get to the end of our consultation, conclude the very, very clear parameters of our policy and then explain it and then justify it,” he said.

Prime Minister Tony Abbott announced on Tuesday that cabinet had agreed to proceed with a plan to force telecommunications companies to store internet and phone logs of everyday Australians so they can be accessed by spy and law enforcement authorities without a warrant.

However, the government has not yet finalised what metadata it wants recorded and for how long.

Mr Abbott originally suggested it could include an internet users' browsing history but later clarified it would not include online “content”.

Similarly, Attorney-General George Brandis struggled to explain what constituted metadata in a now notorious interview on Sky television on Wednesday.

He said authorities would be able to access the IP address, or numerical versions of websites and see what online sites a person had visited, but not what links they clicked on within the website.

Senator Brandis, who is under attack from some of his colleagues for his handling of the now discarded changes to the Racial Discrimination Act, cancelled a speech he was scheduled to deliver in Sydney on free speech, saying he would attend the MH17 memorial service in Melbourne on Thursday instead.

Fairfax Media has learned that Mr Turnbull was not consulted and only learned of the National Security Committee's decision to proceed with mandatory data retention via a leak to a newspaper ahead of cabinet.

Sources say he angrily complained to his ministerial colleagues about not being consulted and having to learn about NSC's decision, not at cabinet, but via the media.

Mr Turnbull said there could be “significant costs” for the telcos if the policy ended up mandating companies store vast amounts of “new classes” of data and said there would then be a question of who would pay to keep and protect the information.

But he said there would be almost no cost if the government decided to legislate that the telcos store information they already hoard.

Mr Turnbull apologised for not being able to spell out more clearly the government's intentions.

“I'm sorry I can't give you the outcome of the policy formation process, we're in an interim process, we're on a journey and until we get to the end of it it's difficult to be more specific,” he said.

Mr Turnbull and Mr Brandis were due to meet staff from Telstra on Thursday afternoon to discuss what implications metadata storage would have on telecommunications companies.

Labor is questioning whether the Attorney-General is up to the job and is calling on Tony Abbott to consider replacing him.

“This Attorney-General, Senator Brandis, is a walking disaster,” the shadow attorney-general Mark Dreyfus said.

“The Prime Minister should be thinking about getting someone in the portfolio who actually understands about the issues that he is meant to be managing, perhaps someone like Malcolm Turnbull,” he said.

With David Ramli, Australian Financial Review

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