New Zealand have suspended Aaron Cruden for two matches after the fly-half missed their flight to Argentina following a night out drinking.
Cruden, 25, the All Blacks' starting fly-half in the absence of Dan Carter, will miss the Rugby Championship matches in Argentina and South Africa.
"I am deeply embarrassed by this lack of judgement and have never been more disappointed in myself," he said.
"I have not only let myself down but, most importantly, I let my team down."
He added: "I carry the burden of shame and disappointment and I am deeply apologetic to my team, to my family, and also to the New Zealand public."
The All Blacks had initially been due to fly to South America on Saturday, but their flight from Auckland was delayed until Sunday by an issue with their plane.
"He went out drinking late in Auckland on Saturday night and didn't make the flight to Argentina," said coach Steve Hansen.
"We are extremely disappointed at Aaron's actions, which are out of character."
New Zealand lead the Rugby Championship by six points after winning three and drawing one of their opening four games.
They will now be without Cruden, who has won 35 Test caps, for the remainder of the tournament.