On Wednesday, Dr McGirr voted against the government's lower house motion that disagreed with the upper house referring Ms Berejiklian to the Independent Commission Against Corruption (ICAC).

Labor, Greens and One Nation MLCs have made claims that former Wagga Liberal MP Daryl Maguire personally benefited from major road projects while in a relationship with Ms Berejiklian.

Speaking outside Parliament on Thursday, Dr McGirr said he supported the ICAC referral due to the "hurried" debate on the government's motion and the "seriousness of the issue at hand".

Dr McGirr said the claims were "a matter that ICAC should consider".

"As I have said on countless occasions, people need to be able to trust the government, they need to be able to trust Parliament and we need to restore and maintain that trust," he said.

"I think on the face of it, these claims have some concern about them and I think people are concerned about them."

Labor MLC Adam Searle brought the ICAC referral motion due to claims that former Wagga MP Daryl Maguire's land holding benefited from the Cobb Highway upgrade at Ivanhoe.

NSW parliament has also head claims that the Country Garden Chinese investment firm associated with Mr Maguire had benefited from advance knowledge of the M9 Orbital motorway route in Sydney.

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Mr Searle told Parliament that the NSW government increasing its spending on the highway upgrade increased from $9.8 million to $62 million over the five years to 2020.

"That is an escalation bringing benefit to the properties along the Cobb Highway and, of course, Mr Maguire's property as well," Mr Searle said.

Mr Searle said it was "a real problem" that Ms Berejiklian was in a "close personal relationship" with Mr Maguire while making decisions on the M9 Orbital tunnel location in Cawdor that could have benefited hundreds of acres of land owned by his business associates.

In moving a motion to disagree with the upper house motion, Liberal MP Alister Henskens claimed the ICAC referral was "trivial and vexatious".

"The proposed referral to ICAC is a bizarre conspiracy theory from Labor," he said.

"It is delusional and it is a sign of how desperate Labor has become. It is seeking any diversion from the leadership crisis that is engulfing the Leader of the Opposition".

Ms Berejiklian was questioned about the road project claims at a budget estimates hearing earlier this month and responded that it was "laughable and wrong and frankly offensive" to allege she made decisions with the aim to benefit Mr Maguire.

Dr McGirr said the budget estimates hearing was not enough to resolve the matter.

"I think this issue stems back to the issue of confidence in the government and our political process and that's the issue for me," he said.

"It's about that confidence and making sure we maintain that trust."

The government had the numbers in the lower house to pass its motion on Wednesday disagreeing with the upper house's ICAC referral, meaning that the corruption watchdog will not be required to produce a report but will still accept the referral.

Country Garden, now known as Risland, has denied receiving confidential information about the M9 Orbital motorway and has denied that Mr Maguire was involved in its Cawdor land purchases.