The Wallabies beat Wales 32-20 in a bruising yet unconvincing World Cup clash in Cardiff to virtually ensure they will avoid South Africa in the finals.

The two-time champions, who had two players sin-binned late in the game, scored four tries but were pushed all the way by a spirited home side who had been on the ropes at 25-3 down at the break.

Australia's win looks likely to pit them against defending champions England in the quarter-finals.

Wales, should they make it through, will come face-to-face with the awesome Springboks.

Australia, who captured their second World Cup title on this ground in 1999, went into the match without inspirational playmaker Stephen Larkham who was ruled out on the morning of the game with a knee injury.

But that was forgotten immediately as they were in front straight from the kick-off when the Welsh defence was punished for not staying on their feet and Stirling Mortlock kicked a grateful penalty from just inside the 22.

Five minutes later, the Wallabies were penalised for collapsing the maul and Stephen Jones, back in the side in place of James Hook, levelled the scores with an ice-cool penalty.

The Wallabies scored a stunning try in the 16th minute.

Berrick Barnes, starting an international for the first time in the place of Larkham, showed remarkable poise to dance between two Welsh defenders.

His pass left centre Matt Giteau in space to score comfortably under the posts for his 18th international try. Mortlock converted to make the score 10-3.

Things got quickly worse for Wales when centre Sonny Parker was forced off with a knee injury to be replaced by Kevin Morgan while skipper Gareth Thomas, in his 99th Test, was also forced out.

He had come off worst in a huge hit from Mortlock and left the field dazed and shattered and was replaced by Hook.

Barnes then kicked a drop goal to give Australia 13-3 lead after 22 minutes before George Smith was penalised for offside but, worryingly for Wales, Jones missed his second penalty.

The Wallabies made him pay again in the 34th minute when they forced a turnover courtesy of a Giteau tackle on Dwayne Peel which allowed George Gregan to kick ahead for Mortlock to score his team's second try, making the score 18-3.

Giteau missed the conversion but the Australians grabbed a third try on the stroke of half-time as a blistering cross-field move involving Lote Tuqiri, Giteau and Drew Mitchell set up Chris Latham.

Mortlock kicked a difficult conversion to make the score 25-3 at the interval.

The injured Australian skipper didn't reappear after the break and his absence unsettled the side as Wales scored a quick pushover try from No8 Jonathan Thomas after the visitors were put on the back foot by a lovely jink from Hook.

Hook added the extras to make the score 25-10 and then slotted over a penalty to cut the deficit further to 25-13 against an Australian side becoming increasingly rattled.

But they were unexpectedly handed a fourth try when Stephen Jones's miserable afternoon got worse when he dropped a testing up-and-under from Latham and the Australian full-back collected and dived over.

Giteau converted for 32-13.

Mitchell was then sin-binned for a high tackle on Welsh hooker Matthew Rees before the Wallabies then lost lock Nathan Sharpe with another yellow card six minutes from time.

Shane Williams took full advantage of the two-man advantage to score his team's second try five minutes from time.

AFP