The 'unprecedented' Aussie 'instability' that concerns Justin Langer ahead of Ashes

Former Australian cricket coach Justin Langer has expressed his concerns about the batting line-up ahead of this summer's Ashes.

The West Australian cricket great has labelled the Aussie top order "unstable", something that England will be able to take advantage of.

Many questions remain about how the top six will come together, with this year's Sheffield Shield tournament set to help shape it.

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Usman Khawaja will open the batting, Steve Smith will bat at four, Travis Head at five, Alex Carey at seven and Cameron Green will be somewhere. The rest is up in the air.

Sam Konstas, Marnus Labuschagne and Beau Webster will be the frontrunners, but the order is far from settled.

"It's unprecedented that Australia go into an Ashes without a really solid top three. England are aware," Langer said, according to The Age.

"There's a lot of talk about that. With their bowling attack, if they can exploit Australia's top order early, then you know that's where they'll be getting their optimism from.

"I think Usman Khawaja has had six opening partners in a year. There's that instability. It can't be healthy. That's the truth.

"We're sort of getting to that point where we're having a shootout every year for the opening batter. The very fact that we're talking about it, and the public are a bit confused about it, that's saying something."

As for Green, Langer would be locking him in to bat at three in the Ashes and developing him in that position.

"He has to bat No.3, in my opinion, because otherwise there's too much chopping and changing," Langer said.

"He batted at three in the world Test championship. He then batted at three in really tough conditions in a three-nil winning series for Australia, and he did a good job.

"He actually showed that he could play in that position. He averages 47, I think, in Sheffield Shield cricket. None of the others average over 40. Cameron Green domestically, you'd have to say is the best performing player and often the best performing player is at No.3. I'd definitely stick with him.

"They've got to find some continuity. It's anyone's guess who the next opener is going to be, but I think he should bat No.3."

Speaking in September, Australian cricket coach Andrew McDonald said Konstas would have to continue performing in the Sheffield Shield to press his Ashes selection.

"I think the contracting system indicates where we think Sam is at. He is a contracted player. It will be debated whether incumbency gives you the leg up," McDonald told SEN.

"I think performance in those Shield rounds is going to be the real connection piece to selection.

"It's about runs and how you get them, that is your currency."

The first Test gets underway in Perth on November 21.