Wanganui High School and Wanganui Rugby Football Union are investigating a violent under-16s schoolboy game that was called off early after a number of fights broke out.
One WHS player was sent off and two more sinbinned before the game on Saturday against Palmerston North Boys High School's U16 B team was canned.
While the game, held at the Wanganui school, was played under the Manawatu Secondary Schools competition banner, WRFU chief executive Dale Cobb said judiciary action may be necessary from his union in a "cold, hard effort'' to send a message to schools and clubs to cut out that play.
"It's absolutely a disappointment and it's something players need to take responsibility for.
"The behaviour is alarming. Players need a reality check," he said.
WHS principal Garry Olver said the school was trying to find out what happened.
While "niggles" could happen from both sides, that was no excuse, Mr Olver said.
"I'm very disappointed, we are making an investigation right now.
"This is clearly a one-off and we will put a stop to it, that's for sure. I won't tolerate this kind of behaviour."
Any disciplinary action and penalties would be the same as if the incidents had occurred during school time, he said.
"Our kids are our ambassadors and when they play for us they represent us."
PNBHS head Dave Bovey said he would also be speaking to his school's team and coach to try to get to the bottom of what happened before hearing "different versions".
"We certainly don't condone any violence on the field and expect our teams to behave accordingly."
Mr Cobb said the WRFU assigned the referee for the game and the incident showed a lack of respect for the officials who volunteered their time.
Recent publicity of school boy rugby violence was a "nightmare" for both the local and New Zealand union, especially after supporting a number of campaigns like Applaud, Zip It and recently the Herald on Sunday's Sideline Champs.
"It's an absolute embarrassment to have it happen in our own back yard. Where's all this aggression coming from? Leave it out of the game, leave it out of your lives," he said.
"It's a trend we need to nip in the bud."
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