An inquiry into data retention has revealed that Telstra divulged customers’ web browsing history to law enforcement agencies without a warrant.

The news comes despite assurances in recent weeks from the federal police and spy agency ASIO that browsing histories could only be accessed by law-enforcement agencies with a warrant.

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The government has come under fire recently for it’s proposed data retention regime, with both Prime Minister Tony Abbott and Attorney-General George Brandis unable to explain what data would be collected.

In a Senate inquiry last month into revisions to the Telecommunications Interception and Access Act, a submission by Telstra indicated it had disclosed personal data to law-enforcement agencies without a warrant included, according to a Fairfax report.

A spokesperson from Telstra confirmed that “in rare cases” it had provided URLs to agencies without a warrant in the past.

“The last time we did so was in relation to a life-threatening situation involving a child more than 12 months ago,” she said.

Agencies that can obtain the data include federal, state and territory police, Medicare, the RSPCA, the Tax Office, Australia Post, ASIO and ASIC.

The Attorney-General’s office refused to comment on the revelations, but said that access to URLs should require a warrant.