New Zealand scrumhalf Aaron Smith has been suspended for one Test after admitting he joined a "female friend" in a public toilet last month.

The World Cup winner has flown home from the All Blacks' trip to South Africa with coach Steve Hansen saying the 27-year-old was "bitterly disappointed" with his actions.

The incident occurred at Christchurch Airport the day after the All Blacks beat South Africa on September 17th, with reports in New Zealand suggesting a complaint had been made by a family waiting to use the toilet.

Hansen said the All Blacks had become aware of the incident after their arrival in South Africa this week and that the sanction had been imposed by senior players in the squad because it was “not of All Blacks standard”.

A series of tweets on the All Blacks Twitter account read: “Halfback Aaron Smith has been suspended for one Test after breaching team standards regarding behaviour, Steve Hansen says.

“Hansen says Smith was seen by entering a toilet cubicle with a female friend at Chch Airport the day after the Chch Test.

“Hansen says Smith accepted his behaviour was not of All Blacks standard. Team leaders decided on punishment.

“Hansen said as a result Smith was not considered for selection for this weekend’s Durban Test.

“Hansen said Smith had asked to return home and team management had supported that.”

New Zealand have already wrapped up the Rugby Championship title ahead of their final match of the tournament against South Africa on Saturday.