Waratahs coach Bob Dwyer says ACT captain George Gregan's behaviour is behind the team's form slump, but Brumbies coach David Nucifora has hit back at Dwyer.

The Brumbies have lost their last three matches, putting their Super 12 title defence in severe doubt, and both Dwyer and former Wallaby David Campese say that Gregan's attitude towards the referees is costing his team dearly.

"It's OK for George to be feisty but there's no need to be arrogant," said Dwyer, who coached Gregan as Australian boss in the mid-1990's. "He seems to assume the attitude that neither he nor the Brumbies can be penalised."

"George Gregan is a very good player, but I don't know how many times the referee had to speak to him. Just get on and play the game," Campese said.

The comments come after Gregan several times questioned South African referee Andy Turner during his team's 19-11 loss to New South Wales at Aussie Stadium on Saturday night, resulting in a penalty and warning over the "verballing" he was receiving.

"It is George's responsibility as captain to maintain the composure and discipline of the team. Dwyer said. "Of course, you have to be competitive but if you are aggressive it doesn't do anything for the team."

Nucifora said he and his coaching panel would have to re-assess their breakdown tactics because South African referees are unfairly penalising them: "We need to do our homework," he said.

But Dwyer dismissed this view, saying the Brumbies were being pulled up by the referees simply because they have been breaking the rules.

"I don't know how many times ACT should have been penalised for launching missiles at the breakdown without being bound," he said.

Nucifora hit back later on Monday at Dwyer's comments, saying that the New South Wales coach should worry about his own team rather than what other sides are doing, and added that Gregan wouldn't be fazed at all by the criticism.

"If he (Dwyer) wants to get personal in the media, that's up to him," Nucifora said. "I think that he showed his ignorance in some of his comments that he made about the scrummaging remarks and he should probably spend a bit more time working out the scrum laws and working on his own lineout.

"He (Gregan) has got a particular way he plays the game. He's very forthright and aggressive and competitive on the field, and that's his nature. I don't think it's got anything to do with arrogance whatsoever. They're ridiculous comments."

Gregan supported Nucifora's view, responding by saying he is on the wrong end of similar claims each year, but he added that nonetheless he had been surprised Dwyer made the comments.

"Similar comments get thrown around each year. You just move on from them," said Gregan. "That's the way I deal with it and that's the way the team's going to deal with it.

"I go out there and I'm competitive and you're obviously playing out there to win and also wanting to make sure you get a fair go in terms of the way the match is being interpreted. As a captain you've got a right to question a decision."

Nucifora also responded to claims by NSW youngster Matt Dunning that the Brumbies game plan is built around a risky "loose-head whip wheel" that relies on prop Bill Young using illegal tactics.

"One thing that came out of that game is that Bill Young is by far the best loosehead prop in Australia," Gregan said. "He's not out there chip kicking out on the full or coughing up the ball in tackles or getting sin-binned," he added in a thinly veiled reference to Dunning.

Young himself also bought into the row by saying that the Waratahs should simply have looked to the result and been happy with it rather than then crowing about what the Brumbies are doing rightly or wrongly.

"I really don't understand why he's made a comment about the game. They had a good win, They should have just left it at that," Young said. "I think it's a bit of inexperience on his part.

"He's a young bloke who's come out and said something silly. I think he'll regret it in the future."