All Black and Highlander Aaron Smith is facing a misconduct hearing after allegedly having sex with a woman in a disabled toilet at Christchurch Airport.

Smith has been stood down from the All Blacks for the game against South Africa this weekend.

He'll face a misconduct hearing on his return to New Zealand.

The 27-year-old halfback was witnessed entering a disabled toilet with a woman at Christchurch Airport on a busy Sunday afternoon last month.

It was reportedly obvious what the two were doing, although the woman was not Smith's partner.

He was in All Blacks uniform at the time.

It's not the first time Smith has been publicly humiliated as a result of private indiscretions.