SYDNEY: Australia is bidding for their fifth World Cup, has not lost in their last 29 tournament games and are the top-ranked one-day team.

But they are not considered favourites by local bookmakers to win the 10th edition on the sub-continent.

The Australians have dominated recent World Cups, winning the last three tournaments, and they are coming off a conclusive 6-1 ODI series win over England at home.

Australia has not been beaten in their last 29 games (one tied) since their last World Cup defeat to Pakistan by 10 runs at Headingley in 1999.

Yet an air of uncertainty over the squad is pervasive in the wake of Australia's Ashes Test series debacle against England last month.

Injuries, selection and form issues are also clouding the team's build-up to their opening game against Zimbabwe on February 21.

Australia's build-up has been far from ideal with key players struggling to be fit to play at the World Cup, headed by skipper Ricky Ponting and senior batsman Mike Hussey.

Ponting missed the entire seven-match ODI series against England recovering from surgery to a broken little finger and has only just resumed batting in the nets ahead of the team's departure.

Hussey, who for so long has been the glue binding together the brittle Australian top and middle order, is considered little chance of playing in the World Cup after a serious hamstring injury as a decision on his availability is delayed.

There were more injury dramas to unfold for the Australians during their ODI series against England with experienced offs-pinner Nathan Hauritz dislocating a shoulder in a tumble while fielding.

Compounding the team's woes, likely spinning replacement Xavier Doherty developed back pain, young all-rounder Steve Smith has hip trouble and batsman Shaun Marsh missed the final two ODI with a hamstring problem.

Australia's durability during the gruelling six-week tournament could be an issue with selectors banking on the fitness of injury-prone pacemen, Brett Lee and short-form specialist Shaun Tait.

By selecting Lee and Tait, as well as erratic duo Mitchell Johnson and Doug Bollinger, Australia will rely heavily on their pace bowlers to be at their best.

Lee performed well in Australia's ODI series win over England, but the 34-year-old and Tait are both on the comeback trail after serious elbow injuries.

Michael Clarke, the stand-in skipper for injured Ponting during the England ODI series, expects the opening partnership of in-form Shane Watson and Brad Haddin to get Australia's innings off to a flying start.

Watson smashed a career-best unbeaten 161, sealed with a huge six to bring up the winning runs against England in the opening match of the England ODI series at the Melbourne Cricket Ground last month.

"I think 'Watto' and 'Hadds' are a wonderful combination. They suit each other. On any given day one can go off and the other can play that anchor role," Clarke said.

"Add Ricky Ponting into that top four and I think we have got a pretty good order.

"The sub-continent conditions will really suit 'Watto' and 'Hadds' and I think over there the first 10 or 15 over are going to be crucial. You need to get off to good starts.

"Our run rates very good lately but we are probably losing too many wickets in the first 25 over.

"In saying that, leading up to the World Cup I think that the first 15 over, it will be crucial to go a little bit harder to maximise the newer ball and the two or three fielders out so it's hard one."

"But the preparation is going well and I think we have been getting off to good starts."

The shock selection was Victorian all-rounder John Hastings, who has only a handful of ODI experience, while David Hussey, Mike's younger brother, also made the squad.

Tasmanian wicketkeeper-batsman Tim Paine, touted by many as a future Australian captain, is part of the 15.