A Northland code of ethics outlining minimum standards of behaviour for players, coaches and spectators has helped prevent the violence seen at children's sports games elsewhere in New Zealand.
"I'm happy it's not happening up here, possibly it's because we have smaller crowds," New Zealand Rugby Union referee education officer Kyal Collins said.
A referee was allegedly punched in the face twice by a spectator at the Auckland secondary schools rugby final on Saturday. Police are investigating the incident, which follows a string of similar attacks nationwide.
The Northland Rugby Referees Association (NRRA) implemented the ethics code, which is administered by individual clubs.
Although there had been a couple of minor incidents at club rugby level, Mr Collins said, "it's certainly no level of the violence we've had down in Auckland".
An event manager was present at all club rugby games to keep spectators in check and help maintain the peace. Referees could call games off if things became too heated, he said.
"If the referee starts to feel uncomfortable or is made aware of a certain individual or a group, then it's up to that person to go and have a word to them."
Auckland Rugby Referees Association chairman Don Crawford said the spectator who assaulted the referee on Saturday was supporting the De La Salle team, which lost the game to Auckland Grammar. Police were called but could not identify the offender.
A concerned group in Auckland launched a campaign in 2009 to deal with the ugly issue prevalent in many sporting codes - abuse from the sideline towards match officials and players.
AUT researcher Simon Walters published a report in March analysing the impact of adult sideline behaviour on children aged 6 to 18 at rugby union, netball and football games.
It found younger children were exposed to higher levels of instruction and more negative comments than their older counterparts.
Mr Walters recommended more club-based coach education to educate coaches and parents about the benefits of creating a positive playing environment for children and youth.
A police spokesman said no data was held specifically on the number of referees or sports officials assaulted by players or spectators during games.
No form of violence was condoned in sport.