BEIJING - World champion Liu Xiang's disqualification from the 110 metres hurdles at the Prefontaine Classic at the weekend was accidental and his hamstring injury is not serious enough to stop him training, according to his coach.

Sunday's third false start in as many races caused further disruption to the world record holder's preparations for his Olympic title defence in Beijing in August, where he is China's best hope of an athletics gold medal.

"It was a relatively small accident, he was just too eager to run well," coach Sun Haiping told the Oriental Sports Daily.

"Over the next month, we will focus on his start in training."

A tight hamstring forced Liu to withdraw from the only other race he planned to run in the U.S., the Reebok Grand Prix in New York the previous week but Sun again played down its seriousness saying at most it would take one to two weeks to clear up.

"His leg injury will not affect our training." he told the Wenhui newspaper.

The disqualification left the 24-year-old with the prospect of starting the Olympics without having had a full run-out against a quality field this season as his original training schedule had him spending the remainder of his time in Beijing.

Sun said there were plans to try and provide Liu with practice under race conditions in the Chinese capital, probably in July.

"We will organise two open simulated meetings at an appropriate time," he said.