NEW DELHI: Former Pakistan captain Imran Khan said on Thursday he was bemused by suggesions that spin wizard Shane Warne should come out of retirement to resurrect Australia's Ashes hopes.

“I have not watched Warne bowl recently, but it can't be easy to play Test cricket again,” Imran said at a promotional event in New Delhi for next year's World Cup in India, Sri Lanka and Bangladesh.

“It is okay to play one-dayers and even easier to bowl in Twenty20, where you have to bowl only four overs. But Test cricket is different where you have to last on the field over five days.”

Calls for Warne's return intensified after England thrashed Australia by an innings and 71 runs in the second Test in Adelaide on Tuesday to go 1-0 up in the five-match series.

A Brisbane cricket fan Ross Heywood even launched a website devoted to raising funds to entice Warne to make himself available for the rest of the Ashes series.

Warne retired in 2007 as Australia's leading Test bowler with 708 wickets.

Imran said Warne's best chance of a comeback would be on the spinning wicket in Sydney for the final Test from January 3.

“Australia will definitely need a spinner, especially in Sydney where the track assists spin bowling,” he said.

“If Warne has to make a comeback it has to be at Sydney.”West Indian great Vivian Richards, who also attended the New Delhi event, was not surprised at the clamour for Warne.

“To go back to Warne shows Australia are in dire straits,” the star batsman said. “They just do not have the bowling attack to take 20 wickets if conditions are not favourable.

“The way Australia are playing in the Ashes shows they are on decline. They are not the best team in the world anymore, they are on the way down.”