Strongly criticising Ricky Ponting's team as a dangerous mixture of arrogance and stupidity in recent series, former Australian captain Ian Chappell has said their priority should be to settle on the best combination for the Cricket World Cup matches.

"Australia's first priority in the Caribbean is to settle on their best side," Chappell said.

"Thanks to a dangerous mixture of arrogance and stupidity during the Commonwealth Bank Series, Australia fiddled rather than found their best combination and then the coach incited the opposition by indulging in ridicule," he was quoted as saying by the 'Herald Sun'.

Australia has two practice matches -- against Zimbabwe and England -- before it plays group matches against Scotland, the Netherlands and South Africa.

"Now they find themselves unsure of who are the best bowlers in the final overs and they are also struggling to unearth a spinner to take a wicket or two in the middle overs after the power plays.

"This is a crucial role and if Australia can't find someone to do the job with (Andrew) Symonds injured, they'll constantly encounter big targets or have their totals, even the larger ones, chased down," he added.

Chappell said after losing the tri-series finals to England and surrendering the Chappell-Hadlee Trophy 3-0 in New Zealand, Australia's loss of reputation would linger longer.

"Australia are now not only a team searching for answers and confidence but are also a side whose aura has faded. This lack of an air of invincibility will be the hardest thing to rediscover," he said.