The government has faced criticism over the former deputy premier's controversial appointment to the $500,000 a year role as Senior Trade and Investment Commissioner, with questions over whether due process was followed.

A parliamentary inquiry into the matter will get underway on Wednesday, while an independent Department of Premier and Cabinet (DPC) review, initiated by Mr Perrottet last week will also probe the propriety of Mr Barilaro's appointment.

The premier says he will not comment on the matter while the independent review, overseen by DPC secretary Michael Coutts-Trotter and conducted by former senior bureaucrat Graeme Head, was underway.

"It's not appropriate in terms of following process for anyone in the government to make a running commentary," Mr Perrottet told reporters on Tuesday.

"We've set up an independent process, please respect that process. Allow that independent review to take place. I will receive the report and I will make that public. I've committed to doing that."

The advice from the DPC was that he was "unable to intervene in the process", he said.

"The report that I expect to receive in the coming weeks I will take on board, I will look at the recommendations, and any action that needs to be taken I will."

Earlier, the premier said it was not his understanding that Mr Barilaro would "walk away" from the job, which was created by the former NSW Nationals' leader when he was trade minister.

The government this month announced Mr Barilaro's appointment after a global talent search by a recruitment firm to fill the high-profile position.

Since then, it has been reported that leaked emails revealed senior Investment NSW bureaucrat Jenny West was about to be named as the successful candidate before Mr Barilaro was given the role.

Mr Barilaro resigned as an MP on October 4.

Australian Associated Press