SIX weeks ago Wycliff Palu couldn't move his arm above his head but the Wallabies' wrecking ball will be looking to show selectors he is fit for the World Cup in tonight's opening game of the new Australian Rugby Championship.

The barnstorming back-rower said his injured right shoulder was at "90 per cent" strength. He will need all that power when he runs out for the Central Coast Rays at North Sydney Oval, with Wallabies assistant coach Scott Johnson sure to be a keen observer.

The Rays take on Sydney Fleet, and Palu, who feared his World Cup dream was over after he suffered the injury during the first Bledisloe Cup match this year in Melbourne, will be given 40 minutes to ease back into competitive rugby.

"I pretty much thought I was no chance for the World Cup when I did it, I couldn't even move my arm over my head," Palu, 25, said.

"It feels a lot better now. I did contact work on Tuesday and Wednesday and there was no pain afterwards. I just haven't taken any big hits on it yet.

"I won't be going out there to score four tries, I will just be trying to play my own game - make my tackles, make my runs.

"This match will give me a good indication to see where I'm at. I am only playing 40 minutes. Next week I am here again, so if the shoulder pulls up fine I will try to do a bit more, lift the intensity.

"I'm pretty confident that I'll be right for the World Cup."

Rays coach John McKee said Palu's presence would give the team a boost. "The plan is to use him as a high-impact player, a front line player in the first half and see how it goes. The amount of field time he has had these last six weeks, I think he will be breathing pretty hard by the end of the half."

Match-fitness is a concern for Palu not only because of his sideline stint but also the new rules applied to the ARC, designed to speed up the game.

"I am probably more nervous about the pace of the game than I am about the shoulder," Palu said. "A few of the boys have told me stories about how fast it is."

Four of the experimental laws were trialled with much success during the Shute Shield, but the ARC will be played under all eight of the Stellenbosch laws, which include a free contest for the ball at any breakdown if players come through the gate. "There will be nowhere to hide," Palu said. "Guys will be flying in from everywhere."

McKee said: "Cliffy gives us two things, huge ball-carrying ability and a hell of a lot of experience. The back-row battle will be crucial to the outcome of the game and having him there is a wonderful learning opportunity for young guys like Beau Robinson and Jared Waerea-Hargreaves."

Palu's opposite, Fleet No.8 Chris Houston, queried: "If I put him out, does that mean I get to go on the plane to France?"

But while the cheeky Randwick skipper is expecting Palu to come out all guns blazing, he doubts whether they'll clash too often.

"The nature of rugby these days, you don't often come up against your opposite number," Houston said. "The only time we'll probably line up against each other directly is at the lineout, and I think he jumps as often as I do.

"He doesn't talk that much on the field, he lets his football do the talking. I might have a line for him in the lineout but he probably wouldn't understand my Scottish accent anyway. Obviously he is a world class player, if I can give him a tough challenge - I am obviously going out to do that."

Palu will be one of seven Wallaby World Cup squad members playing in the first round of the ARC, the others being East Coast's Chris Latham; Ballymore's Sam Cordingley, Berrick Barnes, Greg Holmes and Sean Hardman; and Canberra's Mark Chisholm.

Brumbies lock Chisholm will play at breakaway for the Vikings and will use tomorrow's match against Melbourne at Manuka Oval for much needed game-time.

"Obviously I didn't get a lot of game time in the Wallabies' domestic season and I'm looking to get some time on the paddock and get some extra fitness under my belt," Chisholm said.

Meanwhile, injury has ruled out Western Sydney Rams duo Lachlan Mitchell and Mark Howell from tonight's match against Perth Spirit, with Luke Johnson and Josh Weeks called in.

Ballymore take on East Coast on Sunday at Carrara Stadium.