Former New South Wales energy minister Chris Hartcher and two other State Government MPs have voluntarily withdrawn from the Liberal Party after moves to suspend them over corruption allegations were put in motion.

A senior government source confirmed to the ABC that the party started the process to suspend Mr Hartcher, Darren Webber and Chris Spence last night after they were named in new public hearings held by the Independent Commission Against Corruption (ICAC).

The trio recently re-nominated for preselection in their Central Coast seats.

The ICAC has revealed it is investigating claims the MPs solicited money from various sources in return for favours.

It is also looking at whether Mr Hartcher favoured the interests of Australian Water Holdings after it allegedly made several payments to a company set up by one of his staffers.

Greens MP John Kaye is now calling for a review of all decisions made by the former energy minister.

"The allegations throw a serious cloud over every decision that Mr Hartcher was involved in," he said.

Treasurer Mike Baird says the ICAC investigations into the trio will not stop the State Government from getting on with the job.

"Let's be very clear, if any wrongdoing is found you should throw the book at those individuals, full stop," he said.

"We're going to get on with the business of governing, that is what we were elected to do.

"Clearly we are not going to provide a running commentary."

The corruption watchdog will also hold a second inquiry examining separate allegations that former Labor ministers Eddie Obeid, Joe Tripodi and Tony Kelly misused their positions in parliament to benefit Australian Water Holdings.

A major fundraiser for the Liberal Party yesterday resigned from the board of the State Water Corporation after being linked to the corruption inquiries.

Nick di Girolamon was appointed to the board in 2012.

A directions hearing will be held next month.