Backbench National MP Maurice Williamson has admitted he "overstepped the line" at a conference dinner in Auckland, and has apologised for his behaviour.
The former Cabinet minister was the MC at a superhero-themed dinner at the Esri Users conference last week.
But it's not his "Greatest American Hero" costume that's landed him in hot water – the content of his speech forced some dinner guests to leave the event.
Mr Williamson said in a statement he was asked to be "as entertaining and funny as I possibly could".
However, guests said the MP's presentation displayed pictures of scantily-clad women, and have labelled his comments "inappropriate, crude and sexist".
Mr Williamson has apologised this afternoon.
"It was never my intention to upset any delegates.
"I overstepped the line on the night and did cause offence. For that I unreservedly apologise".
But the apology hasn't convinced Labour's spokesperson for Women, Sue Moroney, who wants Mr Williamson to be publicly reprimanded.
"Not only were his jokes sexist, they were homophobic – from a man who was praised internationally for his 'big gay rainbow' comment during the marriage equality debate," says Ms Moroney.
"This is not the first time Maurice Williamson has used highly offensive humour and he should have learnt by now."
Prime Minister John Key says he hasn't personally spoken to Mr Williamson, but his office has.
"My understanding is that he was there not in his capacity as an MP – that doesn't absolve him of the things he may have said or done, I’m just simply saying I don't think he was there as an MP," says Mr Key.
Mr Key told media he hadn't been informed of the exact content of Mr Williamson's presentation, but he doesn't want to see a repeat of the behaviour.
"Everybody knows that Maurice is a bit flamboyant and a bit sort of out there sometimes – it's not new.
"My office has spoken to him, I'm sure he's had a chance to reflect on it and he'd probably be the first to admit it sounds like he overstepped the line, but I just don't know what he said or did."
Mr Key says the MP's actions are "probably not the threshold for leaving Parliament".
"Instead of dismissing his MP as 'flamboyant' John Key should condemn his toxic comments and demand a full public apology," says Ms Moroney.
The conference organisers, Eagle Technology, were forced to send an apology email to attendees.
"Corallie Eagle, Duane Eagle and all of the Eagle Technology staff offer our sincere apologies to all who attended the NZEUC Conference Gala Dinner last Tuesday night, for the content and references made by the MC, Maurice Williamson," the email said.
"Mr Williamson has asked that we convey his apologies also. His intention was certainly not to offend, but rather to entertain and he regrets the offence caused."
The organisers went on to say they "were not aware of the content that was to unfold".
"We assure you that any offensive comments or content does not reflect the beliefs and values of our organisation."
Mr Williamson resigned as a minister in May last year because he contacted a senior police officer over the arrest of wealthy businessman Donghua Liu.