Police have confirmed they have accessed journalists' communications records to investigate leaks despite the Abbott government's insistence that journalists are not the target of its new data storage laws.

After the Abbott government relented and agreed to give added protection to journalists under its controversial "data retention" laws, Attorney-General George Brandis insisted the laws were aimed at terrorists, paedophiles and organised criminals, not journalists.

He said Labor's demand that police must get a warrant to access journalists' communications "metadata" – such as the time and origin of phone calls they receive – for any investigation into journalists' sources was unnecessary. He said the government was agreeing only to win Labor's support for the reforms in the Senate.

"Media organisations are not the target of this law. The targets of this law are criminals and paedophiles and terrorists," Senator Brandis told ABC radio on Tuesday morning.

But Australian Federal Police Commissioner Andrew Colvin acknowledged in a statement that police had sought authorisations to access journalists' metadata while investigating leaks, though he stressed this was "rare".

Mr Colvin hit back at claims by the Media, Entertainment and Arts Alliance – the union that represents journalists – that the AFP had "been repeatedly asked to hunt down journalists' sources by accessing journalists' metadata" and had done so.

The MEAA said in a statement on Monday that the AFP had admitted this in a meeting last week to discuss journalists' concerns about the laws, which will compel phone and internet companies to keep such "metadata" as the time, origin and destination of phone calls and other communications, for at least two years.

The union said the laws would "encourage at least 20 government agencies to go trawling through journalists' metadata".

But Mr Colvin said this was "inaccurate and a distortion of the comments made".

He said in the past 18 months, the AFP had received 13 referrals relating to unauthorised leaks of Commonwealth information – which is a breach of the Crimes Act with a penalty of up to two years' jail.

He said there was no need to access the journalists' metadata in the "overwhelming majority" of these cases.

"AFP requests for accessing a journalist's metadata are rare," Mr Colvin said.

The data retention laws are set to pass with Labor's support after Prime Minister Tony Abbott this week agreed to Labor's demand that police and government agencies be forced to get a warrant if they are requesting metadata in order to establish the identity of the source of a leak.

Normally, agencies do not need a warrant to access metadata, only internal authorisation.

Media companies say the use of the term "warrant" is unclear and, unless it's a contestable court order, the proposed laws could still be exploited to expose whistle-blowers.

Media chief executives are preparing to travel en masse to Canberra on Friday to appear before an inquiry into how the laws will affect journalists - though the enquiry could be called off if the government presents its amendments on journalists' safeguards before then.

Eight media organisations, informally known as The Right To Know Group and comprising Fairfax Media – owner of The Age – News Corporation, the ABC, SBS, Guardian Australia, Seven West Media, Ten Network Holdings and Nine Entertainment Co, have joined forces in their opposition to the bill.

Police and security agencies such as ASIO insist that communications metadata is an essential tool for fighting crime and terrorism. But the capability is being eroded because firms are increasingly discarding the data after a short period as they no longer need it for billing purposes.

with Jared Lynch

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