North Queensland NRL coach Paul Green is facing a $10,000 fine after being issued with a breach notice for his spray at the referees after the Cowboys' loss to Melbourne.
Green is the second coach in as many weeks to be reprimanded for slamming the performance of match officials, joining St George Illawarra's Paul McGregor.
NRL head of football Brian Canavan said that, like McGregor last week, Green had crossed the line in his criticism of the game's whistleblowers.
"The comments by Paul Green about the officials were unprompted," Canavan said.
"As with recent comments by a fellow head coach which resulted in a breach notice, these statements crossed the line relating to our rules regarding match officials."
Canavan also warned other coaches to expect similar punishment should referees continue to come under fire in post-game media conferences at the business end of the year.
Green and McGregor's attacks had come after Canberra counterpart Ricky Stuart escaped sanction for his broadside at officials.
South Sydney coach Michael Maguire also recently complained about the referees' use of concussion protocols for star halfback Adam Reynolds.
"We will continue to ensure the integrity of the referees is protected in the lead-up to and during the finals," Canavan said.
"There are avenues for coaches, players and club officials to take up matters with the referees rather than making public comments."
Green accused the referees of ruining last week's game against the Storm.
"That was the worst display of refereeing I have ever seen. There were some calls where they lacked consistency," Green said after the Friday defeat.
"I'm not one to shift the blame away from our performance.
"But the fans deserved more than that. There were two quality teams out there and I was left scratching my head at some of the calls.
"I said to the boys after the game, I've never been involved in a game where so many things have gone against us. It's just a shame the refs ruined the game."