UPDATED 4.11PM: The Prime Minister has issued an apology but claims he was just "horsing around" when he made a female waiter uncomfortable by pulling her hair while she was at work.

The waitress published her account of the incidents on a the left-wing Daily Blog site, saying John Key pulled her ponytail several times over the course of several weeks last year, despite repeated requests that he stop.

She claims Key would sneak up behind her and "just couldn’t help himself", also writing that he gave her two bottles of wine "which felt like a bribe." 

John Key is en route to Turkey for ANZAC commemorations at Gallipoli. 

Key had this to say when asked by One News if his behaviour was appropriate:

"In hindsight no," he said. "But in the context of, you know, we have lots of fun and games there lots of practical jokes and things and it's a very warm friendly relationship.

"In that context you'd say yes, but if you look at it now, no."

"Yeah, there's always horsing, lots of horsing around and practical jokes and look, that's all there really is to it."

He said he never intended to make to make the waitress uncomfortable and has apologised.

The Prime Minister frequents the Auckland cafe with his wife Bronagh, who was supposedly present when the hair-touching took place. 

Workers at the cafe told Newstalk ZB that staff were too busy to comment. 

Green Party co-leader Metiria Turei has branded Key's actions weird and unacceptable.

"There's never any call to touch people without their consent."

"This is bullying behaviour by somebody with authority over a person who's doing a service job and he should have known better."

She believes the incident is a window on the attitudes of men in the National Party, comparing Key to Aaron Gilmore, a low-ranking National MP who resigned after it emerged he berated a waiter in Hamner Springs.

"It's very Aaron Gilmore-esque," Turei says. "An apology is one thing but he shouldn't be doing it."

"The Prime Minister should not be going around touching people without their consent. Certainly not pulling people's hair."

Labour leader Andrew Little says framing it as a light hearted incident shows it's not a real apology.

"Even if he thought it was OK to do it once, and I don't think it was, he did it repeatedly when she continued to object and he thought it was a great joke."

The National Council of Women has written an open letter to John Key claiming that he joins a list of people outed for sexism.

The letter says the council is disappointed to learn of the unwanted touching - but appreciates the apology.

Council of Women chief executive Sue McCabe says it's hard for women to speak up when a man says he was "well intentioned", and it plays into a culture of sexism. 

"Now that his eyes have been opened to how easy it is for sexism to occur and cross the line, that he steps up and does a bit more to reduce sexism and its effects in our country." 

The council is happy to meet with Mr Key to discuss how sexism is playing out in our society.

Human Rights Commissioner Jackie Blue says it's never acceptable to touch someone without their permission, and there's no exceptions.

Newstalk ZB's Political editor Barry Soper is travelling with Key to Turkey and says the incident is extremely bizarre and difficult to explain.

"Even his wife told him to desist pulling this woman's ponytail, but he continued to do it. So it's bizarre behaviour and it's certainly something that the Prime Minister won't want to have to field questions about on this trip to Gallipoli, but field questions he will."

Soper says it's the last sort of story the Prime Minister wants breaking.

"He wants to concentrate obviously on the matter at hand, and that's remembering the war dead in Gallipoli and of course then going on to a trade mission to the Gulf.

"But it's a bit difficult to understand what the PM intended by it."