Michael Ennis' abuse of referee Gerard Sutton and the time-wasting tactics by the Canterbury captain in Thursday's night's 21-14 loss to South Sydney has been deemed "unacceptable" and has resulted in a warning to match officials, players and clubs that such behaviour won't be tolerated in finals matches.

NRL head of football Todd Greenberg said protocols were put in place at the start of the season about communication between captains and referees and he expected those to be properly enforced.

Ennis waged a running battle with Sutton at ANZ Stadium that many felt should have had the whistleblower act on his repeated threats to sin-bin the Bulldogs hooker.

Greenberg and referees boss Tony Archer were particularly disappointed Ennis was able to manipulate a warning from Sutton that Canterbury faced losing a player to the sin bin after conceding three consecutive ruck penalties near their own line late in the first half. It created a long stoppage while he talked to the referee and the Rabbitohs waited to take the tap to restart.

"We cannot have players badgering the referees to get an unfair advantage," Greenberg said. "Last night was unacceptable and not what I expect.

"We have the protocols in place to keep the game moving and we want it enforced. Let's be clear, for penalties with no caution or warning, there will be no communication between the referee to the captain or any player.

"That reminder has been communicated to the referees today through Tony Archer and players and clubs should also listen carefully to ensure they comply. The rules are in place but we have reminded the referees today that they should only allow captains to approach them during the major breaks in play.

"There is to be no more badgering referees after penalties and scrums. The fans want the game to keep moving and we have the rules in place to ensure that happens. Now it is up to the referees to enforce it."

Greenberg said he was disappointed the protocols introduced at the start of the season hadn't been followed and he admitted Sutton was as much to blame as Ennis, who received a similar warning in 2012 from former NRL referees boss Stuart Raper after dropping the F-word five times while talking to referee Jason Robinson during a match against the Sydney Roosters. 

On Thursday night, Ennis swore at Sutton after a penalty was awarded against Bulldogs prop Aiden Tolman for knocking the ball out of Jason Clark's hand as the Rabbitohs replacement prepared to play it.

"Bullshit. C'mon, that's not fair," Ennis told Sutton, who said: "I will not accept that, I won't accept that. Come here, listen Michael, you had the opportunity to talk, not to swear at me."

Ennis replied: "I said that's bullshit. We are grown men, we are grown men, mate. That's footy". 

Former NRL referee's boss and the game's best known whistleblower Bill Harrigan said, at that stage, Sutton needed to think of a quick-witted response such as: "Well, let's play and act like it."

At the start of the season it was revealed Ennis was the captain who approached referees more than any other player last year (39 times) and he and Manly's Jamie Lyon (31) approached referees more than Paul Gallen, Cameron Smith, Johnathan Thurston, Robbie Farah and Sam Thaiday combined.

Harrigan said Ennis had "played" Sutton like a "seasoned pro" and believed the referee needed to follow through with his repeated threats to use the sin bin.

"He [Ennis] got exactly what he was after, which was to slow the play down," Harrigan said. "I have got no doubt that, when Gerard Sutton gets off the field and does his debrief, he will say, I handled that poorly and I can do a hell of a lot better.

"The time that I think he thought he was going to go to the bin, he was as nice as pie. He had already been warned and he got called out and, again, you could see him thinking, 'I am in trouble here', and he was trying to backtrack real quick. Whereas every other time he stood up there in his face. I was thinking, he is just playing the game, this bloke, he was all over [Sutton]."