Marcus Harris will open the batting with David Warner in the first Ashes Test at the Gabba, chairman of selectors George Bailey has confirmed.

Harris' place at the top of the order had presumed to be in doubt, having been in and out of the team for three years.

But he is the incumbent after partnering with Warner the last time Australia played Test cricket - the agonising defeat to India at the Gabba in January. Bailey, however, has placed faith in the 29-year-old to nail down his spot.

"It gives you great confidence as a selector when you know your opening batters are locked away as far as a Test series go," Bailey told RSN radio. "It's a hard spot to bat and to get those places settle, it's really important.

"Harry's only had a limited opportunity in the past, and he's been in and out a bit, so we'd love nothing more than for him to hopefully to get an opportunity to get an extended run at it.

"What we have liked is his consistency. He's obviously been a prolific run-scorer at domestic level here, but also love the fact he went overseas and had a great year for Leicester as well."

Harris fell cheaply in both innings of Victoria's recent Sheffield Shield clash with NSW, but he did score a gritty century against the Blues last month. After 10 Tests, Harris is averaging 23.77 and his top score of 79 came against India at the SCG in 2019.

Will Pucovski, who made his Test debut as an opener against India last season, has seen his chances of being part of the Ashes recede after another concussion which means he has yet to play for Victoria this summer.

Bailey confirming the opening combination will come as sweet relief to Harris, who had been staring down some blistering form from Queensland veteran Usman Khawaja. But Khawaja could still earn a spot in the middle order for the first Test on December 8, with Bailey saying the No.5 spot "is certainly open" although he added the selectors were close to a decision.

South Australia captain Travis Head has been in promising form and could win back the spot he lost after last year's Boxing Day Test.

The Australia selectors are expected to announce next week 25 players who will join up in Queensland to also form an Australia A side, for both an intrasquad warm-up and a match against England Lions. The final Ashes squad may not be confirmed until after the intrasquad fixture which could play a similar role to the one that took place ahead of the 2019 Ashes in England.

While only the No. 5 slot would now appear up for debate there will be jostling for positions among back-up quick bowlers. James Pattinson's international retirement means the tag of first reserve is up for grabs. The uncapped Michael Neser has picked up a hamstring injury in the current Sheffield Shield match although it is hoped it will still be available. Sean Abbott, Jhye Richardson, Mark Steketee and Scott Boland could also be in contention.