The Wallabies are preparing for a scrum onslaught at Twickenham on Saturday (Sunday morning AEST), with England to turn to their set piece when under pressure.

The scrum is the cornerstone of England's game, despite boasting attacking weapons in the backline.

Poite is regarded as the best referee of the scrum in world rugby and Marler is set to come under the microscope after boring in on Wales' tighthead prop last weekend.

It's a move that can assert scrum dominance, but should be penalised.

"So much of the scrum is based on perception," Dwyer told British media. "The English work on having a reputation for legal scrumming while doing the opposite. If I was [Wallabies coach] Michael Cheika, I would be asking the referee is that [Marler angling in] allowed.

"Let's hope they are not allowed to do that because England won a few penalties against Fiji that I would have awarded in the opposite direction."

So much of the focus of the build-up has centred around the scrum. It's the perceived weakness of the Australian team and England have been their chief destroyers in years gone by.

The Wallabies have tried to rebuild their set piece under Argentina's Mario Ledesma with a philosophy of "all eight push straight".

Cheika said after the Wallabies were bullied by England at Twickenham 12 months ago that his forward pack was "too honest", in a jab at England's scrum tactics.

But while the Wallabies are laying low and trying to avoid getting England's big men fired up, Dwyer didn't hold back.

"It [illegal scrum tactics] must be by design," Dwyer said.

"Neither [Marler or Mako Vunipola] scrummage square. Both of them angle in.

"...You only have to look back to a couple of years ago and England were loathe to start with Marler because even though he was good around the park, his scrummaging was not up to standard.

"Now we have a situation where he is allowed to scrummage at 45-90 degrees, he has become a very good scrummager. I find that impossible to disregard."

Former Wallabies coach Eddie Jones believes Australia can beat England if the scrum holds solid. England are in danger of being knocked out of the tournament in their own backyard if they lose to the Wallabies.

It would be a disastrous end to the World Cup for the hosts. It comes 12 years after England took their chance to deliver a cruel blow to Australia when Jonny Wilkinson kicked an extra-time drop goal to beat the Wallabies in the final in Sydney.

"It will be some game but if the Australian scrum holds up - and the actual number of the scrums in a game is a big factor - I'm tipping Australia," Jones said in the Daily Mail. "If they win their share of ball, they have just a bit too much around the park.

"And I'd back whoever wins the pool to get all the way through to the final."