New South Wales Transport Minister David Campbell has apologised for wrongly claiming that journalists hacked into the transport blueprint website.

The company in charge of the website has admitted it was possible to get access to the information before the blueprint's public release.

The company, Bang the Table, previously claimed the site was hacked.

On Tuesday, Mr Campbell told Parliament police were investigating how details of the blueprint were obtained in advance by the Sydney Morning Herald.

He alleged the blueprint site was hacked by people, including journalists, prompting the Sydney Morning Herald's editor to say his staff "may well be hacks, but they are not hackers".

In a statement, Bang the Table says while the front page of the blueprint site was password protected, other pages were temporarily accessible.

Mr Campbell was in the hot seat in Parliament today, where he apologised for making the claim.

"I made yesterday's statement in good faith and based on information provided to me by Bang the Table," he said.

"That information was wrong and accordingly I apologise. Now it is time for Bang the Table to apologise."

Mr Campbell told Parliament the State Government had now terminated its contract with Bang the Table.

The Opposition have called for Mr Campbell to be sacked because of the hundreds of millions of dollars wasted on the axed CBD Metro.