A man who went public over Aaron Smith's antics at Christchurch Airport now wishes he'd kept quiet.

The man is apologising to the All Black who, as a result, left South Africa in disgrace and faces a misconduct hearing.

The man, who was at the airport that day with his family, said in an email to the NZ Herald he regrets going to the media, and never imagined the story would become so big.

He and his wife have had a lot of abuse since the toilet tryst surfaced, and he wants to formally say sorry to both Smith and the rugby union.

He adds he won't be releasing a video he has.