Former Maori All Black captain Rua Tipoki has admitted he assaulted a man at a party in Tolaga Bay in 2015.
The 42-year-old pleaded guilty to assault with intent to injure four days into a jury trial at Gisborne District Court.
Tipoki's father, Reihana Tipoki, 66, was jointly charged but has since been cleared.
The Tipokis had name suppression but it lapsed with the guilty plea on Thursday.
The assault charge related to an incident at a 21st party on November 29, 2015, at a rural property near Tolaga Bay.
The Crown said the victim was walking down a farm track in the dark when he was attacked by Rua Tipoki.
The man was knocked down with a punch and then punched four or five times while he lay unconscious.
The Crown alleged that Reihana Tipoki supported or encouraged his son during the attack.
It was understood that the attack had its origins earlier in the evening, when the victim claimed he had seen Tipoki taking seafood from a marine reserve.
Tipoki claimed the complainant was the aggressor, badgering him with allegations of illegal fishing during the party.
Tipoki has been remanded on bail until sentencing on November 21.
A midfielder or first-five, he played his rugby for North Harbour, Bay of Plenty and East Coast at provincial level as well as the Crusaders, Blues and Highlanders in Super Rugby. He captained the Maori All Blacks in 2007.