The lure of Sun City and the richest prize in golf has proved too powerful for Lee Westwood and caused a rift between the world number seven and the Australian Golf Union.

Westwood has joined Tiger Woods and 10 other world-class golfers in southern Africa to compete in the Million Dollar Challenge instead of defending his Australian Open title in Adelaide.

But he denies adding injury to a perceived insult by returning the £8,500 trophy he won 12 months ago in a damaged state.

Colin Phillips, the AGU's executive director, said that an explanation was sought from Westwood's manager Andrew Chandler after the £8,500 trophy had to be repaired by a Melbourne jeweller.

Westwood, seeking to end his season with a third consecutive win, said the chance to play Sun City - and compete for a £625,000 first prize - was impossible to resist. From there he commented: He added, "the trophy was returned on September 21st and duly signed for by the Australian Golf Union as being received in perfect condition.

"I am surprised that two days prior to the Million Dollar Challenge and the Australian Open they have decided to air their grievances."

According to Phillips, the cup was broken at the base and had dents in the top when officials opened its velvet-lined shipping box. The AGU also claim that they learnt indirectly that Westwood, the world number seven who beat Greg Norman in a play-off for the Australian Open title last year, was not defending the crown.

But on that Westwood countered: "I withdrew on September 2nd explaining I had been invited to play in the Million Dollar Challenge with the world's top 12 golfers.

"It is a terrific opportunity for me to play against the world's best and I believe that any other professional golfer would have made the same decision."

The Ryder Cup star added that, schedule permitting, he looks forward to playing in the Australian Open again in the future.

This is not the first time this year that Westwood's withdrawal has upset organisers.

He and stable-mate Darren Clarke were both criticised for pulling out of the Western Open in Chicago the week after the US Open in June.

He also withdrew from the MCI Classic in South Carolina the week after the Masters in April, citing tiredness after a long spell in the States.

In Sun City Westwood is trying to finish his season with a third successive victory, having won twice in Japan last month to take his tally of successes this year to seven.

Colin Montgomerie, Mark O'Meara and Ernie Els are also competing in the star-studded field for the richest prize in golf.