Prime Minister John Key says All Blacks player Aaron Smith has "let himself and those close to him down", after Smith was caught entering a disabled toilet cubicle with a woman at Christchurch Airport.
The incident happened on September 18, following the Rugby Championship Test match against South Africa.
"There's no question [he let himself down]. He'll have to reflect on that, and I'm sure the NZ Rugby Football Union will reflect on that," says Mr Key.
The 27-year-old was stood down for this weekend's Test against the Springboks in Durban after details emerged of his behaviour. He'll now face a misconduct hearing.
"On our arrival to South Africa on Monday we were informed on this," said All Blacks coach Steve Hansen.
"I had a conversation with Aaron who confirmed the story.
"As a result of this the leadership group met and were unanimous in the fact the behaviour wasn't acceptable and as a consequence a one-match suspension would be put in place.
"Clearly Aaron is bitterly disappointed in his behaviour and feels he has let the team down but just as importantly he feels bitterly disappointed in letting his family and his partner down.
At his request has asked to go home to deal with the personal matters that have come with this incident and we are happy to support him with that."
Mr Key says Smith will be "pretty disappointed in himself".
"And I think the Rugby Union, coming off the back of a couple of other pretty poor PR issues in recent times, will want to send a strong message to the All Blacks that they set a high level of expectation of their behaviour and Aaron clearly didn't meet it."
However, Mr Key has defended the All Blacks for their leadership and off-field behaviour.
"What I would say as a general rule in defence of the All Blacks, they have been, for the most part, very good role models in the past 10 or 20 years under Richie McCaw's leadership and more recently Kieran Read, they do a lot to try and prove to young New Zealanders that they're the sort of people to look up to."
A female witness said she was disgusted with what she has seen.
The woman, who was at the airport with her husband and young son, said she decided to speak out because that kind of behaviour was not acceptable of a high-profile role model.
The husband and wife took their young son to the bathroom.
They were waiting for him outside the unisex cubicle when a young woman walked towards them and entered the cubicle.
Moments later Mr Smith walked down the hallway and entered the same cubicle.
She said the pair were in the bathroom for about 10 minutes and noises could be heard, adding that their young son was oblivious to the situation
It is not the first time Mr Smith has courted controversy. In 2012 he was benched for a Test against South Africa in Dunedin for breaking a team curfew, and two years a later a naked selfie of him was posted online.
"This was really bad decision-making by Aaron which reflects poorly on him, and on the team," says New Zealand Rugby Chief Executive Steve Tew.
However, Mr Key doesn't want to rush to judgement on Mr Smith.
"You can't hold him responsible for other issues that happened, they are individual events so it's about proportionality here," Mr Key says.
"I suspect he'll be sitting back reflecting on the fact he's let himself down, he's let the team down. He's an integral part of the All Blacks and he won't want to be sitting on the sidelines.
"Frankly, he's embarrassed himself a bit."