Mitchell Marsh was over-promoted in his role as joint vice-captain of Australia's Test team according to Shane Warne who said the allrounder had not done enough to justify his position in the side.

Marsh was handed the vice-captaincy in a job share alongside Josh Hazlewood last month, but with the fast bowler unavailable for the series against Pakistan, Marsh was the only one present in the UAE.

He is now facing a fight to keep his spot in the side after making just 30 runs in four innings with the recent leadership role creating a potential complication given the strong endorsement handed to him.

"I hadn't thought even before that series that he'd established himself in the team," Warne said. "He's done okay, but I don't think he's cemented his spot and that's why it was a strange selection as vice-captain."

Marsh averages 26.08 in 30 Tests but had appeared to enjoy a breakthrough period last season when he scored two centuries in three matches against England, in Perth and Sydney, and following that with 96 in the opening Test against South Africa in Durban.

Since then, however, he has amassed 110 runs in 11 innings and is among a group of players now sweating over their position for the India series which starts in December. Though his bowling is seen as a valuable second string, he has only taken six wickets in his last 11 Tests.

The added challenge for Marsh is that, like his brother Shaun who is also under pressure after a lean series in the UAE, he could well be involved in Australia's limited-overs sides for much of the next month which would cut down the opportunity to find red-ball form in the Sheffield Shield.

Mitchell is also joint vice-captain of the T20I side, along with Alex Carey, and so currently remains the UAE for the three-match series against Pakistan which starts on Wednesday. After that, Australia play a home series against South Africa (ODIs and a T20I) and India (T20Is) before the Test series against the latter.

Warne had more encouraging words for Shaun Marsh, who Australia coach Justin Langer said was unlikely to be left out of the one-day side to open up more Shield cricket given his strong returns on the tour of England.

"I'm a huge fan of Shaun and Mitchell Marsh. Just because they have a couple of bad test matches there, suddenly you can't remember all the good stuff that Shaun Marsh has done," Warne said. "Hopefully he gets a bit of an extended chance. But Mitchell Marsh needs to go and make some runs."

In what is currently open season on Australia's Test team, Warne threw a few names into the mix for potential call-ups including the left-field notion of D'Arcy Short, citing the example of David Warner who transferred his white-ball skills to the Test arena, despite Short averaging just 23.58 from nine first-class matches.

"When you think about D'arcy Short, think about David Warner," Warne said. "They said he was just a white-ball player. Now he's one of the best players in the world."

Like the Marshes, Short could get just one Sheffield Shield outing before the Test squad is selected if he continues to feature in Australia's one-day side.

"There definitely is a lot of spots open I guess," Short told AAP. "All I can do is score runs in white-ball cricket and whatever comes from that, I'll be happy to take it."