Top player Rua Tipoki is being investigated by rugby officials after he was involved in a clash with a teenage player while watching a high school match.

The former Crusaders, Blues and New Zealand Maori team member was on the sideline at a junior sevens tournament match between Ngata Memorial College and Gisborne Boys' High School in Ruatoria, near Gisborne, on Wednesday.

The Weekend Herald was told that Tipoki "clotheslined" a player - a term used in sport to describe someone placing his outstretched arm in a runner's path at neck level.

But father-of-four Tipoki, 36, said last night that he ran onto the field at Whakarua Memorial Park from the halfway mark after a brawl broke out at the try line.

"There were three players on one boy at one stage," he said.

"I've tried to come in and grab one of the boys and he's stepped out of my reach and I've clipped him on the chest and he fell straight on his bum."

Ngata Memorial College principal Karen McClutchie said she believed the police might be called.

"We'll be working with the police as part of an investigation. I believe it is up to the victim if he wants to lay charges."

The school was assisting the East Coast Rugby Union, which is holding its own inquiry.

Graeme Summersby, chairman of the union's judicial committee, confirmed it was investigating an incident at the game.

Tipoki was suspended for 16 weeks in 2006 while playing for the Blues for striking Western Force player James Hilgendorf and fracturing his eye socket.

Last year, he was banned for two weeks after being cited for punching another player during the Heartland Championship.