The new deputy leader of the NSW Liberals, Stuart Ayres, will be asked about a controversial $5.5 million grant to a regional shooting club when he fronts up to a corruption inquiry into his former boss.

The NSW Independent Commission Against Corruption is investigating whether former premier Gladys Berejiklian breached the public trust when she supported projects proposed by her secret lover, Wagga Wagga MP Daryl Maguire.

One of those projects – a multimillion-dollar upgrade to the Wagga Wagga Clay Target Club – was also supported by Mr Ayres, then sports minister.

Mr Ayres will give evidence to the inquiry on Friday, rounding out the first five days of the public hearings.

Bureaucrats in the NSW Office of Sport were sceptical about the project when Mr Maguire put it forward in 2012 and then again in 2016, dismissing it as “low priority” because it would compete with a state-owned Sydney facility.

As well, there was insufficient detail to back the proposal, former Office of Sport executive director Paul Doorn told ICAC.

But ICAC heard this week, Mr Ayres gave the office a single day to prepare a document he could take to Cabinet’s powerful expenditure review committee to advocate for the project to be funded.

The public servants were in the dark about the reason for the urgency.

As treasurer in 2016, Ms Berejiklian controlled the agenda for the expenditure review committee.

Discussion between her and Mr Ayres’ offices led the shooting club proposal to end up being discussed, and approved, at a December 2016 meeting of the committee.

The ICAC heard on Thursday that Ms Berejiklian was perceived as instrumental to the decision to revisit a business case that found the funding proposal didn’t pass muster.

The revision meant that the club qualified for the $5.5 million grant, which it eventually received.

On Wednesday, former premier Mike Baird told the inquiry he was “incredulous” to learn of Ms Berejiklian’s relationship with Mr Maguire.

“I think it should have been disclosed,” he said.

Ms Berejiklian, who denies wrongdoing, stepped down as premier on October 1 when ICAC announced it would be holding the public hearings examining her conduct.

She will appear as a witness on Thursday and Friday next week.

Former deputy premier John Barilaro will give evidence on Monday. Mr Maguire will follow suit on Wednesday.

-AAP