A Marlborough rugby referee has quit over what he calls unbearable sideline abuse.

Premier grade referee Grant Sinclair said he had had enough of constant criticism from players and coaches, some of which had become personal.

Sinclair told the Marlborough Express newspaper he wasn't prepared to put up with the grief anymore , giving up his free time to be abused.

"I've been refereeing in Marlborough for five years and I think it has got worse over the last two years.

"I don't think the coaches are playing a big enough role in disciplining their players to respect the referee's decision."

The New Zealand Rugby Union said referees citing sideline abuse as their main reason for resigning was a rare event.

NZRU community and provincial union general manager Brent Anderson said there had been about 50 reported cases of referee abuse this year, below the average of 80 such incidents, from 70,000 games of rugby.

There had been three cases of physical abuse of a referee this season.

Marlborough Rugby Union has issued the warning of a ban to clubs after several reports of players, coaches and parents abusing referees from the sideline during matches, and sometimes after games.