Perrottet has insisted the call was not a threat and said his government remained united.

“We have a very strong team here in NSW,a very strong team that has transformed our state,” he said on Friday.

He also said he was not aware if a photograph existed of him wearing the uniform.

“I’m not aware of that,but it’s not about that. It’s about the fact that I did it,and I’m truly sorry for that mistake that I made.”

Earlier on Friday,Perrottet wrote an open letter to the Jewish community and released a video in which he again apologised for wearing the costume.

In the video published to social media the premier said he hoped some good could come from his “grave mistake”,after he met Jewish leaders on Thursday afternoon.

“We spoke about how important it is to continue to raise education and understanding particular for young people of the horrors of the Holocaust to ensure evil such as that never occurs again.”

Perrottet said he had worn the rented costume at the party attended by friends and family – a decision he now describes as “a grave and terrible mistake”.

“When I was 21 at my 21st fancy dress party I wore a Nazi uniform. I’m deeply ashamed of what I did,and I’m truly sorry for the hurt and the pain that this will cause people right across our state and particularly the Jewish community and Holocaust survivors,” he said on Thursday.

In his open letter to the Jewish community released on Friday,the premier said he took full responsibility for his actions and hoped “something good can come from this terrible mistake”.

“To you,the Jewish community,Holocaust survivors and your families,I am deeply sorry. The choice I made when I was 21 has no doubt caused distress,” he wrote.

“There is no excuse for my actions. While I can sincerely say they did not reflect in any way my attitude towards the Jewish community,they did demonstrate my naivety and insensitivity to the pain and trauma experienced by so many because of the vile ideology represented by that costume.”

Perrottet said he had sought the advice of the leadership of the NSW Jewish Board of Deputies.

Deputy Premier Paul Toole said on radio 2GB on Friday that Perrottet had the support of the National Party and denied that the revelations could derail the Coalition’s pitch for a fourth term of government at the looming state election.

“I think what we’ve actually seen is from Dominic yesterday,he admitted that he’s actually done something stupid. But we’ve all done something stupid. We’ve all done something that’s been insensitive,” he said.

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