Ryan Cross is poised to make his starting debut in the Wallabies' biggest Test of the year after skipper Stirling Mortlock was ruled out Australia's Bledisloe Cup opener against the All Blacks on Saturday.

Mortlock has failed to recover sufficiently from concussion after sustaining a head knock in last Saturday's 16-9 Tri-Nations defeat of the world champion Springboks in Perth.

"We had hoped that, with time, the symptoms would resolve themselves, but that hasn't happened soon enough for this match, so we've made the call early," Wallabies coach Robbie Deans said.

Mortlock was the inspiration behind Australia's memorable, drought-breaking win over New Zealand in Melbourne last year and his absence is a major blow for the Wallabies, who can shoot to the top of the Tri-Nations table with a repeat victory over the All Blacks.

Cross, though, has been in superb touch all season, earning Western Force Player of the Year honours after a brilliant Super 14 campaign and then bagging a tryscoring double after coming off the bench against France in Sydney three weeks ago.

With Cross set for promotion, fellow rugby league convert Timana Tahu is also likely to be elevated from Australia's 30-man Tri-Nations squad into the Wallabies' match-day 22 when Deans names his team on Wednesday.

Flanker George Smith will assume the captaincy from the resting Mortlock.

While Deans had to scratch Mortlock, his counterpart and fellow New Zealander Graham Henry bracketed his skipper, champion flanker Richie McCaw, alongside Daniel Braid in the All Blacks back row.

McCaw is rated a 50-50 chance of making his comeback after a month in the stands with an ankle injury.

In addition to the Mortlock setback, the Wallabies on Tuesday also had to contend with accusations that they cheat at scrum time.

All Blacks prop John Drake claimed the Wallabies' pre-engagement against South Africa was illegal.

"I can't believe they got away with what they did at scrum time with their technique of entering," Drake told ABC Radio.

"The biggest thing I probably got out of the Test is the way that they probably cheated at scrum time.

"They pack very high, similar to what the Crusaders and the All Blacks did about three years ago.

"When they say 'crouch', they're still high so the other team has to try and come up to them. It kind of puts them off, and then the Australians just dive straight down. I was pretty annoyed with that."

Wallabies flanker Rocky Elsom said such accusations were nonsense.

"That's probably the last thing we want to do because when the scrum gets collapsed, we get penalised first. That doesn't help us."

Indeed, the Wallabies scrum has been universally maligned in recent years, with referees tending to blame Australia's perceived shortfalls for the set piece collapsing rather than suspect weakness from opposing packs.

New Zealand assistant coach Steve Hansen less directly claimed Australian halfback Luke Burgess spun the ball into the scrum to deliver quick, easy possession against the Springboks.

He suggested Burgess rolls the ball in so it shoots quickly through Australia's front and second rows directly to the feet of No.8 Wycliff Palu.

"They're clever with the way they do things, you've only got to look at the way the halfback puts the ball in," Hansen told journalists in Wellington.

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