Wallabies get a boost for the opening Bledisloe Cup test with positive Petaia prognosis

Injured star Jordan Petaia will be available for the opening Bledisloe Cup Test with Wallabies coach Dave Rennie saying he expects to settle on his line-up in the coming days.

Petatai injured his hip during the Super Rugby AU final and while he hasn't trained fully with the squad, Rennie expects him to be in the mix for the Wellington Test on October 11.

The 20-year-old centre has only played two Tests and his short career has been disrupted through injury but he offers the Wallabies' backline genuine X-factor which they desperately need to be any chance of breaking an 18-year Bledisloe drought.

"He's getting better; the injury is not as bad as first feared," Rennie said from their Christchurch hotel quarantine.

"He didn't train with the team at all last week so we're hoping we will get him back up and running by the end of the week.

"At this stage we expect everyone to be available for the first Test."

It's Rennie's third quarantine, having done so when he arrived into Sydney from the UK and then again when he shifted to Queensland, but this one has been made a little easier with the ability to go outside into a garden area at the hotel.

After their three-day lockdown they will be free to train in small groups on Tuesday and as a full team on the sixth day after their second COVID-19 test.

But the coach has piled up the players with in-room workouts and video analysis, aware that time is short before their opening Test.

"We've had to prioritise what we need to get through and then we can build our game as we go," he said.

"We're trying to cram in as much as we can as well as trying to get some physical work in."

Rennie said there were still positions up for grabs and the final line-up would depend on how they trained in the lead-up to the Test.

He's standing by his mantra of "if you're good enough, you're old enough", hinting that at least some of the 16 squad rookies will make their Test debut.

"We've always said we're going to pick on form ... there's no doubt some of the young men are going to put serious heat on a spot within that 23," the Kiwi said.

"There are a number of positions where it's tight and some may depend on combinations but how some people train may tip the scales in the next few days."

Following the two New Zealand Tests the Wallabies will come up against their former coach Michael Cheika in the Rugby Championship after he signed on as an assistant with Argentina.

But with such a large turnover of players, Rennie isn't bothered about Cheika's inside knowledge.