John Key was on his way to Gallipoli when ponytail-gate was making headlines and is expected to face questions on the incident in Parliament today.
Speaking on Radio New Zealand this morning, Mr Key said he didn't have an issue with physical interactions with people because he took "thousands" of selfies each day and had people coming up to him and putting an arm around him on many different occasions.
"It's a fairly tactile world we live in," he said.
Mr Key revealed he had taken legal advice as a private prosecution had been launched against him, and the waitress looks set to take court action of her own.
The "casualness" of his character was considered a strength in his role as Prime Minister, Mr Key said, but that would change in the wake of ponytail-gate.
"That behaviour has to change and it will change, I accept that fully," he said.
He also revealed Judith Collins could be back in Cabinet if a post became available.
Mr Key told Radio New Zealand that Ms Collins' return to Cabinet was subject to a position being made available.
The Prime Minister said an MP whose brother was facing indecency charges would not be stepping down because it would set a precedent that could extend to other family members.
Mr Key said he took advice on the issue when the MP approached him last week to inform him of the court case.
"A minister shouldn't have to step down because one of their family members has a problem that they're dealing with," he said.
Mr Key told Radio New Zealand he regretted his actions and he hoped he had not embarrassed New Zealand.
The incident was reported in media around the world.
"Clearly I've misread the situation," Mr Key told Radio New Zealand. "I can absolutely assure people it was really meant in good humour and nothing else.
"But every person on the planet would accept that I should have read that situation better. And I clearly didn't and I regret that and I've apologised sincerely for it."
He said he did not believe it was sexist behaviour and he "could've" done it to a man.
"There is a bit of context there. And the context was a very good natured environment that we were in and it was very much a sort of thing in jest. So yes, technically it would have been possible."
Serial litigant Graham McCready is preparing a private prosecution, claiming that Mr Key committed assault.
Waitress Amanda Bailey, 26, is also considering legal action and is getting advice from Unite Union.
Mr Key said his legal advice was "just a natural part of the process I need to observe".
He added: "On the basis that the District Court or others ask questions I obviously need to be in a position to respond to that."
