NSW Premier Mike Baird has warned colleagues found to have acted improperly in the lastest corruption probe that he will be their “worst nightmare”.

Mr Baird says he’s determined to restore the public’s trust in his government amid explosive claims at the Independent Commission Against Corruption (ICAC) about the Liberal Party.

“I don’t care what political badge you have,” Mr Baird told reporters on Wednesday. “If you have done wrong and if ICAC has shown you have done wrong, then I am your worst nightmare.”

The ICAC has heard allegations the NSW Liberal Party’s main fundraising arm helped funnel banned donations back to the party.

The corruption probe has already seen four Liberal MPs, including a minister, relegated to the cross bench.

Mr Baird, who replaced Barry O’Farrell after the last round of ICAC hearings, said he would do everything in his power to clean up state politics.

“The actions we take will be strong, they’ll be swift and the community will see that we’re determined to fix and ensure that events that have been unravelling for many weeks down at ICAC do not happen again,” he said.

His comments came after a veteran NSW Liberal MP dragged into the inquiry said he felt he was being used when he was asked by fellow MP Chris Hartcher’s office to make a Freedom of Information application in 2010.

At the time, Charlie Lynn believed the request was about sharing the burden of the $30 application and did not question it. But he said he now realised he was being used.

“I like to do my bit and help where I can and I usually don’t question those sorts of things,” Mr Lynn told reporters. “But look, I didn’t think that I’d ever end up before ICAC for giving a $30 cheque to somebody without asking for any personal favours.”

Mr Lynn is not accused of any wrongdoing and says he has warned for years about “snake oil spivs” in the Liberal Party’s ranks.

The ICAC has heard allegations the Freedom of Information (FOI) request was designed to help Mr Hartcher dig dirt on ex-Sydney Water managing director Kerry Schott and that one of his staff arranged for Mr Lynn’s office to make the application to conceal the request’s origin.

Dr Schott was locked in a dispute with Australian Water Holdings, the Obeid-linked firm that allegedly donated $183,000 to Mr Hartcher and his associates via a “sham” company, EightByFive.

Mr Lynn on Wednesday agreed the FOI application might have been his first.

Asked in the witness box if he was a friend of Mr Hartcher’s, Mr Lynn replied: “There are no friends in politics, you know that.”

He agreed that he and Mr Hartcher were both members of the party’s Right, and that he had respected the sidelined energy minister, but described the faction as loosely bound.

“I think they call it the IKEA faction – you get it together when you want something to work,” Mr Lynn said.

“Does it come with its own Allen key?” ICAC commissioner Megan Latham quipped.

Mr Lynn said consecutive ICAC inquiries and the unfolding donation scandal had damaged the Liberals.

“The links to developers, the lobbyists on state executive, the peddlers of influence, the snake oil spivs that inhabit the party … they’ve actually fractured their integrity and that’s going to take a long time to heal,” Mr Lynn said.

He said new premier Mike Baird was the man to restore the party’s integrity.