A waitress who shamed New Zealand Prime Minister John Key for repeatedly pulling her ponytail said Thursday she spoke out because of a "moral" obligation to tell the public about his bad behaviour.

New Zealand media identified the hospitality worker as 26-year-old Amanda Bailey, who works at Rosie Cafe in Parnell, the upmarket Auckland suburb where Key lives.

Bailey revealed the bizarre behaviour on Wednesday in an anonymous blog post that labelled Key a "schoolyard bully", prompting an apology from the prime minister.

The conservative leader has not challenged her version of events but insists he was simply "horsing around".

In a second post on left-wing website thedailybog.co.nz published after she was identified, Bailey said she told her story because "the public has a right to be aware how badly their prime minister has behaved".

"I contemplated the lasting effects this was bound to have on my near and not-so-near future, surely not worth it, but I made the moral decision to put myself second and tell the truth," she wrote.

"There is no shame in telling the truth."

Bailey's original post detailed how Key pulled on her ponytail time and time again over several months, despite her obvious displeasure.

"He was like the schoolyard bully tugging on the little girls' hair trying to get a reaction, experiencing that feeling of power," she said.

The ensuring row has generated international headlines and sparked heated debate in New Zealand about Key's behaviour.

His parliamentary opponents have described the 53-year-old's actions as "weird", "childish" and "totally unbecoming of the prime minister".

New Zealand First leader Winston Peters said Key's hair tugging appeared to constitute common assault and questioned why police officers in his security detail had not stepped in to prevent it.

"The police are in a most invidious position. I am not saying what they should do, I am asking why they didn't do anything at the time," he told Radio New Zealand.

"After all they may be bodyguards but they are policemen and women."

The controversy has become an unwelcome distraction for Key as he travels to Turkey for a sombre ceremony to mark 100 years since the Gallipoli landings involving Australian and New Zealand troops.
Source: AFP