The Wallabies have dismissed the ongoing saga surrounding their World Cup presence as "peripheral" and "irrelevant" as they turn their focus to a showdown with Argentina at Twickenham.

World Rugby fanned the fire by releasing a statement to say that Craig Joubert's decision was wrong in awarding the Wallabies' a last-minute penalty against Scotland that allowed Bernard Foley to boot Australia to a 35-34 win.

It has caused massive friction between nations and Wallabies coach Michael Cheika became the unlikely referee ally by describing World Rugby's actions as "unfair" to Joubert.

But the players are avoiding getting stuck in the middle, letting Cheika be the face of their defence and choosing to move on to their semi-final preparations.

Asked if the best way to deal with the Scotland fallout was to get on with the tournament, halfback Will Genia said: "It's irrelevant. We are still here, we won the game, we have another week to prepare.

"People can say what they want. We are just concentrating on Argentina.

"[People] can forget about it or talk about it all they want. We have forgotten about it, it doesn't matter. It's irrelevant."

The Wallabies got "somewhat positive" news on prop Scott Sio's shoulder injury and will give him until later in the week to prove his fitness.

Israel Folau and David Pocock did not train with the team on Tuesday, but the pair is expected to be ready to play against Argentina.

Winger Rob Horne is also available for selection for the first time since the Wallabies beat England three weeks ago after recovering from a shoulder injury that was initially thought to have ended his World Cup campaign.

Joubert has been overlooked for refereeing duties in the two semi-finals this weekend.

Wallabies assistant coach Stephen Larkham backed Cheika's defence of Joubert after he ruled a Scotland player to be offside despite the ball appearing to touch Australian halfback Nick Phipps.

"You can certainly look at every game this year and there was a contentious decision by a referee, whether it was in the first minute or the 80th minute, that you can probably harp back on," said World Cup-winner Larkham.

"We've had different ways of winning in this campaign so far and we got through that last game. There were some things we didn't do as well as we should have. There were things we got away with and things they got away with. We put that to bed and we'll move on to Argentina now."

The Wallabies have lost to Argentina just twice since 1997, but one of those defeats triggered the demise of Ewen McKenzie as coach last year.

Argentina are the dark-horse in the southern hemisphere battle for the World Cup title.

They survived a second-half scare to trounce Ireland 43-20 last weekend and have already beaten South Africa this year.

The Wallabies won a Rugby Championship battle 34-9 in July, but are refusing to take the Pumas lightly.

"At the end of the day we are concentrating on preparing for a semi-final of the Rugby World Cup against Argentina. All the other stuff is peripheral," Genia said.

"We were obviously disappointed in a lot of areas of the game [against Scotland]. Defensively our first-up tackles weren't good enough … and just our attacking ruck as well.

"Traditionally, having played [Argentina] before they are a very passionate side … but we are just concentrating on ourselves. There is so much room for improvement."