Gutted after being denied a last hurrah with Matt Giteau, Berrick Barnes has shifted his focus to the Wallabies' Tri-Nations tilt on Saturday night.

Barnes could not hide his disappointment after Australian Barbarians teammate Giteau pulled out of Friday night's Gold Coast clash with Canada due to a groin complaint.

It loomed as his final chance to combine with his mate in national colours after a France-bound Giteau controversially missed World Cup selection.

Barnes clearly rued the missed opportunity after Giteau failed to show for the Barbarians camp on the tourist strip.

"Unfortunately a niggle made him unavailable - he didn't make the trip up," Barnes told AAP.

"It would have been a good opportunity to play together again, that's for sure."

But Barnes looked at lifting his spirits by filling the TBA bench spot left by Wallabies coach Robbie Deans for the Tri-Nations finale against New Zealand in Brisbane.

Armed with five Sydney club games since returning from footballer's migraine, Barnes hopes to cap his unorthodox comeback with a standout game for the Barbarians.

"I would love an opportunity to be on the bench," Barnes said.

"But we will see how it pans out and who comes through unscathed tomorrow night."

Barnes - a flyhalf who can also play inside centre and fullback - appears to be vying for a bench berth with Barbarians teammate and fellow World Cup squad member Rob Horne.

But it was someone who won't be travelling with him to the World Cup who was on Barnes' mind on Thursday.

The 25-year-old said he felt for Giteau after Deans brushed the 92-Test veteran and opted for Barnes as back-up playmaker to Quade Cooper in his 30-strong Cup squad.

Giteau was there when Barnes made his Wallabies debut in 2007.

And they combined to inspire a World Cup win over Wales in only Barnes' second Test when Stephen Larkham's injury thrust him into the starting side.

"He's obviously a class player," Barnes said.

"I have played with and against him for about five years - we go back.

"I can't say anything other than we were both working hard for a spot and the cards fell my way this time."

But Barnes added: "I am definitely disappointed for him.

"He is a bloke who can cover a hell of a number of positions and up until last year he won the John Eales Medal (in 2009) - but it is what it is."

Giteau - who remains a shadow Wallabies player before resuming his career in France for Toulon - pulled out of the Barbarians along with Ben Daley (shoulder) and Mark Gerrard (calf).

Giteau is replaced at inside centre by Ben Tapuai, Gerrard by Bernard Foley and Daley by Ben Lucas - both on the bench.

World Cup members Barnes, Horne, James Slipper and Tatafu Polota-Nau are coming off the injury list along with Drew Mitchell, who has played just 21 minutes of club rugby since a four month lay-off with a dislocated ankle.

Nathan Sharpe will skipper a Barbarians side also featuring back-up Wallabies halfback Nick Phipps.

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