It found the coach guilty of using threatening words or actions and grabbing the referee’s shirt.
However, it did not substantiate any further allegations of referee assault during or after the match, the union said.
Chief executive Tanya Dearns said according to the New Zealand Rugby Disciplinary Rules, the behaviour could have resulted in a 23-match suspension.
“After considering both the mitigating and aggravating factors, the suspension was reduced by eight matches, resulting in a 15-match ban from coaching or any involvement with teams playing matches,” Dearns said.
“Respect for referees is fundamental to the integrity of the game,” she said.
“We take these matters very seriously and are committed to maintaining a respectful environment for all participants.”
Mid Canterbury Rugby Union said heightened emotions among sideline supporters after the final whistle might have contributed to the incident and this would be addressed directly with the club.
A police spokesperson said officers were called to the ground but no charges had been laid.
