Gallacher had no option but to quit: Baird

NSW Premier Mike Baird says Mike Gallacher had no option but to step down from the ministry after allegations he acted corruptly.

Mr Baird described claims made at the Independent Commission Against Corruption (ICAC) against Mr Gallacher as "serious".

"I have had a discussion with the police minister (and) there was no option other than for him to resign," the premier told reporters in Canberra.

He insisted he would take every action possible to clean up politics in NSW.

"Every action required to restore confidence in NSW will be done under my leadership," he said.

Mr Gallacher will make a statement on Friday afternoon.

The ICAC earlier heard Mr Gallacher was involved in a "corrupt scheme" to funnel illegal donations to the NSW Liberal Party.

The corruption watchdog heard a top executive at Nathan Tinkler's Buildev group had Mr Gallacher and former Liberal frontbencher Chris Hartcher "on tap", thanks to tens of thousands in secret donations.

Mr Baird said he would clean up NSW politics.

"My job is to fix it and I give an assurance that that's exactly what I'll do," he said.

"There's no doubt that you'd rather it did not happen, but it did.

"I had to take those actions today in relation to the police minister.

"I'm convinced the people of NSW will continue to see the good work we are doing."

Mr Gallacher says he only heard about the allegations for the first time on Friday morning.

"I don't know what the allegation is," he told a press conference in Sydney.

But he said he resigned to ensure the government was not distracted by the claims.