HIS impact off the St George Illawarra bench has been pronounced but burly English prop Mike Cooper admits he is still adjusting to the rapid speed of the NRL and the refereeing.

The Dragons are still smarting after they were walloped in the penalty count against South Sydney last weekend, which prompted coach Steve Price to admonish his side at times for their ill discipline during Wednesday's session in Wollongong.

Cooper lamented the Dragons' inability to control the ruck in their past two losses and said his settling-in period wasn't quite complete after an education in the English Super League.

"We've had some harsh calls, but there were a fair few calls that were right having looked at the video," he said. "We have to be better than that.

"With just the one referee, if you're dominant back home in a tackle [in the English Super League] you can hold them down for a long time.

"If you're in attack and get hit you're getting worked over a lot more at home. They allow you to do it.

"They [NRL referees] are always in your ear to move once you hit the ground. You've just got to be switched on all the time."

The opportunity to test himself against players like Melbourne's galaxy of stars was the reason Cooper left boyhood club Warrington to join the Dragons this year. He will remain in the Red V until the end of 2015.

He's been one of the Dragons' best through the opening five rounds but warned of the need for the Dragons to find consistency as they try to snap a two-game slide.

"It couldn't be a harder challenge after a big defeat like that [against the Rabbitohs] for us," he said.

"One of the things I'm excited about is going down to Melbourne.

"We get a chance to play against world-class players and it's going to be a great experience for me.

"It's going to be a real test to see where we're at," Cooper said.

"Hopefully I can perform well and help the team, which is the most important thing."