The Communications Minister made the comments during an appearance on Bloomberg TV on Thursday, saying that “commentary has got ahead of the policy”.

“Metadata is a term that means different things to different people,” he said.

“What have to do is get the end of our consultation, conclude the very, very clear parameters of our policy and then explain it and justify it.”

Mr Turnbull’s remarks follow an interview by the Attorney-General George Brandis, who struggled to explain details of the proposed policy.

He later cancelled a public appearance at a free speech forum in Sydney.

Mr Turnbull said metadata was already recorded by companies, primarily for billing purposes.

“Telephone companies record who called whom and how long the call went for, where the call was made from - that’s what’s called metadata,” he said.

“That material is retained, has always been retained originally for billing purposes. It is very important potentially, potential information to be accessed by security services and police services in an appropriate manner.

“What we’re doing at the moment, I’m working closely with the Attorney-General to review our arrangements relating to mandatory data retention.”

Mr Turnbull could not confirm potential costs of the proposed legislation, saying it could range from no cost to a “significant cost”.

“Then you’ve got the question of who should bear that cost,” he said.

Mr Turnbull also weighed in on the continuing rollout of the National Broadband Network, which he described as a “very poorly planned project” with new management in place.

“It’s like turning an oil tanker around,” he said.

“It takes a while.”