Lealiifano faces six months out

The 25-year-old, who suffered the injury when his leg was caught under a Waratahs defender late in the Super Rugby match at Canberra Stadium, would undergo surgery in Canberra on Monday, the Brumbies said.

While a big blow for the Brumbies, the loss of the in-form Lealiifano further limits Australia's playmaking stocks ahead of June Tests against Scotland and Wales.

The Wallabies have already lost regular fly-half Quade Cooper to a long-term knee injury sustained during last year's World Cup, while utility James O'Connor is not expected to be fit after suffering a lacerated liver in an on-field clash for the Melbourne Rebels last month.

The injuries leave Kurtley Beale, who played fly-half in the absence of O'Connor in the Rebels' loss to the Bulls over the weekend, the likely candidate for a starting role at fly-half for the Wallabies.

Australia play Scotland in Newcastle on June 5, before a three-match series against Wales in Brisbane (June 9), Melbourne (16) and Sydney (23).

"That's it, he's gone for the season. Whatever the outcome of the surgery he won't be back for the Brumbies this year which is a big blow for both Christian and the team," Brumbies coach Jake White said after the Waratahs game.

"It's not ideal, we spoke about in the change room and it's not great but it's just another challenge that's been thrown up to the group."

Lealiifano's loss opens the door for Robbie Coleman or Zack Holmes to slot into the fly-half position for the Brumbies, who are top of the Australian conference and well-placed to secure a berth in the play-offs of the southern hemisphere provincial tournament.