He said when he went over to tell them to move the man spewing on his car turned around and started verbally abusing him.
"He looked like he wanted to fight me," he said.
"I sponsored rugby for quite a few years but I started seeing things like this happening ... they are just acting like bloody idiots."
He said sponsors would start pulling away from clubs if they heard this type of thing was going on at their club.
Kahukura Rugby and Sports Club president Warren Lawrence said the club had investigated the incident and was looking at disciplinary action.
"In terms of outcome we are bound by the Bay of Plenty Rugby code of conduct as well as our own club policy," Mr Lawrence said.
"We have initiated proceedings to deal with the situation."
Rotoiti Sports and Community Association president Bruno Gardiner said while teams were playing away from home they were responsible for their code of conduct.
"The code of conduct is left up to the management of the respective teams when they are travelling."
He said they held monthly meetings to check on the behaviour of each team, with any incidents being dealt with on a case-by-case basis: "For something serious we can stand players down for a couple of games or put them out of the club altogether."
Rotorua police area commander Inspector Bruce Horne said misuse of alcohol was a problem not only in sports clubs but for every community in the country.
"One of the particular problems blighting New Zealand communities is the practice of pre-loading, which involves people consuming a large amount of liquor ... before going out to socialise at a tavern or club," he said.
"In respect of sports clubs ... there is a great opportunity for friends and family to exercise a positive influence on others at the club to drink in moderation and act responsibly."
