MP calls for Perrottet's head over costume

Senior colleagues are backing NSW Premier Dominic Perrottet after revelations he wore a Nazi uniform to his 21st birthday party, despite a leading crossbencher calling for his head.

Several ministers including at least one potential rival for his job are standing by the beleaguered Liberal leader but Shooters, Fishers and Farmers boss Robert Borsak insists Mr Perrottet should go.

"I'm not offended by the actions of Premier Perrottet, I am disgusted," Mr Borsak said on Friday.

"No amount of grovelling apology can make amends for a flawed personality."

Mr Borsak, whose Polish father was detained in concentration camps in Poland and Germany even though he was not Jewish, said Mr Perrottet could not apologise his way back to integrity.

"You have none," he told the premier. "Get out while you still have a chance".

Mr Perrottet says he has no intention of quitting amid the fallout, after disclosing his controversial costume choice on Thursday amid rumours about the 2003 party.

With the government already hobbled by the departure of multiple MPs in the lead-in to the March state election, other members of the parliamentary crossbench have also expressed disbelief.

"The premier and I are of a similar age and I could not even fathom dressing in that way in any occasion," Independent MP for Sydney Alex Greenwich told ABC Radio National on Friday.

"There is absolutely no excuse for it".

Greens MP Jenny Leong said, "fascist extremism is not a joke. People living every day with racism can't simply shake it away with a quick press conference like this government tried to do".

"The people of NSW deserve and expect so much more".

Mr Greenwich declined to say whether he would offer support for Mr Perrottet in the event of a hung parliament. The Greens declined to comment on the premier's leadership.

Meanwhile, deputy Labor leader Prue Car emphasised the government was "in chaos" two months from the election.

"This is a government that seems to be intent on destroying itself," she told reporters.

"The Liberal party are more focused on internal brawling ... than actually governing NSW."

Flanked by outgoing ministers Brad Hazzard and Victor Dominello, Mr Perrottet said on Friday he had overwhelming support from colleagues since confessing to his "naive ... mistake".

"But ultimately it's not about me," he told reporters.

"It's about the hurt ... that it caused many people across the state.

"It's not about politics. It's about doing what's right.

"I am focused now on really ensuring that people don't make the same mistake that I did all these years ago."

Asked if he was confident of leading the Liberals to the March 25 election, Mr Perrottet answered with a terse "yes" several times.

He referred to the coalition's infrastructure track record over 12 years as instilling confidence in voters.

Mr Perrottet's confession was prompted by a private warning on Tuesday from a cabinet colleague, identified by multiple media outlets as Transport Minister David Elliott.

He dismissed on Friday suggestions Mr Elliott had threatened him with the revelation, saying he wouldn't delve into "private discussions".

Mr Dominello said the premier had owned and apologised for his mistake.

"Absolutely, I back him in every day of the week," he said

Other senior coalition figures including Nationals leader Paul Toole and potential leadership rival, moderate Liberal Matt Kean, have publicly backed Mr Perrottet.

Shaking, red-faced and at points close to tears during his press conference on Thursday, the premier said he did not understand the gravity of what the Nazi uniform meant when he put it on.

Asked where he saw the humour in wearing a Nazi uniform, he suggested all people matured differently based on their experiences.

"I am not the person I was when I was 21," he said.

The incident came a year after Mr Perrottet joined the NSW Liberal Party and two years before he was appointed president of the NSW Young Liberals.