WALES remain hopeful Scarlets centre Scott Williams will be fit for Saturday's showdown with Australia at the Millennium Stadium.

The 2012 Grand Slam winner missed his country’s uninspired 17-7 victory over Tonga on Friday night after suffering a toe injury.

The 23-year-old picked up the knock during his excellent performance in the record 40-6 win over Argentina the week before as Wales bounced back from a 24-15 defeat to South Africa.

Warren Gatland has a centre crisis with British and Irish Lions stars Jonathan Davies and Jamie Roberts out injured while Cory Allen, who won his first cap against the Pumas, is also unavailable for the Wallabies clash.

"Hopefully, Scott Williams will be available for next week," Wales coach Gatland said.

The Six Nations champions are looking for their first triumph against a former Tri Nations side since they overcame Australia 21-18 in 2008.

Young centres Owen Williams and Ashley Beck both scored tries and impressed against the Tongans as they partnered each other in the Wales midfield for the first time.

But Williams’ return would be a welcome one for the hosts because he is richly experienced, a 2011 World Cup veteran and his famous try in Twickenham last year helped Wales win the Triple Crown there for the first time in a last-gasp 19-12 success.

Cardiff Blues centre Williams, 22, and Ospreys centre Beck, 23, both staked a claim for their place against the Aussies on the weekend.

"The two guys both scored tries and it was the first time they had played together as a combination," said Gatland.

"A lot of those guys, when you throw them in for the first time against a lot of seasoned internationals, we expect a lot from them.

"I think we are pretty happy with how they performed. They will be critical of their own performances, and that is what we expect from them."

Wales laboured to victory over Tonga after building up an early 17-0 lead only to butcher several try-scoring chances of adding to their advantage, enjoying 90 per cent possession in the second half.

Wales captain and number eight Ryan Jones, who led by example on Friday night, confessed they have to up their game if they are to beat the Wallabies for the first time in eight matches. "We need to be more accurate," said Jones. "Scoring opportunities need to become tries, the best teams in the world are clinical when they are presented with opportunities.

"We will see the introduction of guys who have had a week off, so they should be fresh.

"It bodes well and we have a bigger pool of players to pick from now.”