Sideline abuse is making rugby referees quit - and jeopardising the future of the senior game in Northland.
Eleven senior referees have quit in the past year, fed-up with the weekly barrage of aggression and threats from team supporters.
Northland Rugby Union operations manager Kyle Collins said the lack of respect was also putting younger people off becoming rugby referees, and there was now a critical shortage of refs in the region.
"We're down to about 40 for 52 clubs in Northland and that's only going to get worse," he said.
"We know the average referee age is on the wrong side of 50, and that's not great for quality refereeing, simply because the older you get, the slower you get."
A veteran Northland rugby referee is also calling time on spectator abuse.
Retired police officer Gavin Benney said the mood of many team supporters at senior club matches was now so hostile that one young Northland referee was recently threatened with a knife.
"Last year, I was coaching a young referee. He was 18 years old. He was having a pretty good game and doing all right so with about 15 minutes to go I decided to go and watch another game, and another [trainee] ref.
"So I left him there, and at the end of the game he was approached by a parent of one of the players who threatened to knife him."
The offender's side had lost by 100 points, yet the parent still wanted to take it out on the referee.
Mr Benney said Northland had lost 11 senior referees in the past year because of sideline abuse, and it was time for the remaining referees to crack down.
"This is not about referees being precious. You expect a bit of challenge. But things have gone way too far," he said.
"We need to stop the game, and refuse to restart it until the abusers have gone."
Abusers banished to behind the posts
The abuse at junior rugby games was eventually stopped, Mr Benny said.
He has been employed for the past season by the Junior Rugby Board to bring order to the sidelines at the many junior rugby games played every Saturday at Whangarei's Kensington Park.
Patrolling the sidelines, and having a quiet word with the abusive shouters eventually worked, he said.
"Probably 30 years of police work, dealing with people has helped. You don't get heavy, you just say, 'Hey, we don't do that here anymore'."
It had also helped that the Junior Rugby Management Board had made some of the worst offenders, coaches and reserve players, stand behind the posts.
"So they can yell all they want and no-one can hear them. I think they've decided now there's not much point yelling," he said.
"They hate it, but it's worked."
Mr Collins said Northland clubs urgently needed to find ways to control sideline aggression.
"We have a code of ethics, and the clubs are supposed to provide event managers to patrol the sidelines, but they're low on volunteers, and it's just been lip service really - it hasn't worked," he said.
"So I plan to scrap that, and we will work on a document we can all buy into that will work, " he said.
That could possibly involve the strategy that has proved effective for junior rugby: forcing coaches and reserves to stand behind the posts.
Who's the ref?
The rugby officials are not sure why spectator abuse has become so virulent of late.
But one dad - in Whangarei this week to watch his son play in an under-15's tournament - told RNZ he suspected it had to do with the advent of the video ref in professional games.
Craig Hamlin said that had in some ways undermined the authority of referees on the ground, who could never hope to see everything that happened on the field.
Supporters now felt more entitled than ever to point out things the ref might have missed, he said.
"It's hard to keep quiet, because you do see more than what the ref can see.
"I noticed it today, people calling out things from the sideline that the ref missed."
But no game could work with 100 referees, he said.
"And it just makes it harder for the players and the refs."
Mr Collins said the clubs had let spectators get away with bad behaviour for too long.
He now hopes to bring the clubs and refs together with Mr Benney and forge an agreement to curtail sideline abuse, protect the refs and players and put the sport back into club rugby.