Former NSW deputy premier John Barilaro told his chief of staff that the plum US trade commissioner role was the job he wanted when he left politics, an inquiry has heard.

Mark Connell this morning made a statement to the parliamentary inquiry investigating Mr Barilaro's controversial appointment, which comes with a $500,000 annual salary package and is based in New York.

Mr Connell said he had a conversation with Mr Barilaro in April 2019, after a meeting with the then treasurer Dominic Perrottet and minister Stuart Ayres.

"He said, 'I've just come from a meeting with Dom and Stuart regarding trade'," Mr Connell wrote in his statement.

"'And we're going to bring back the Agent General in London as well as a bunch of other postings around the world'."

The former chief of staff claims Mr Barilaro then added: "This is it; this is the job for when I get the f*** out of this place."

In the statement Mr Connell said the conversation continued.

"I responded to Mr Barilaro and stated, 'but John, the Agent General role will be filled well before you retire from this place'," Mr Connell said.

"Mr Barilaro then said, 'I don't want to go to London, f*** that, I'm off to New York'."

Mr Connell said he pointed out that the current office was in California.

"Mr Barilaro responded and stated, 'I'll get them to put one in New York, that's where I'm off to'," Mr Connell said.

Mr Connell worked for Mr Barilaro as his chief of staff from April 2017 to December 2019.

Mr Barilaro has strongly denied he said those comments. 

"I completely refute the statement by Mr Connell," Mr Barilaro said.

"The conversation he has recalled is fictitious, false and only serves as a reminder as to why we had to part ways."

He said the public was not being shown the full picture of what had occurred. 

"If this inquiry is genuine in its intent to understand the process and the truth by which I was appointed, then surely I would be called up to provide this detail immediately," Mr Barilaro said. 

"The continued drip feed of select information from the inquiry into the public domain goes against all procedural fairness."

NSW Premier Dominic Perrottet said he was not aware of Mr Barilaro making the comments. 

"The former deputy premier, Minister Ayres and I had numerous discussions in 2019 in relation to the establishment of Global NSW, and at no point in any of those discussions, was it ever raised that the former deputy premier may want to hold a position as a trade commissioner," Mr Perrottet said.

The Opposition has described the revelation as "explosive".

"This important revelation probably confirms what many suspected," Opposition Leader Chris Minns said.

"If true, this position was created for a friend, that the selection process was rigged and that there has been a month long cover up." 

Mr Minns said the Premier needed be asking questions of his team. 

"We all need to have the answer as to how and whether any other cabinet ministers in the New South Wales government were aware of this scheme.

"And if they were what steps will the New South Wales Premier take to rectify this." 

The parliamentary inquiry has previously heard evidence that in mid-2021, Mr Barilaro's office inquired about changing the recruitment process for the trade commissioner roles to be ministerial appointments.

Mr Barilaro then went to cabinet in September with a submission to change the process, which was successful.

It meant that former bureaucrat Jenny West, who had been verbally offered the New York job, had it rescinded. 

Mr Barilaro then left politics and applied for the job in a second recruitment round.

He's now withdrawn from accepting the position.