The ceiling of a Cambodian factory that makes Asics trainers collapsed on workers killing three people and injuring seven, in the latest accident to spotlight lax safety conditions in the global garment industry.

About 50 workers were inside the factory south of Phnom Penh, the capital, when the ceiling caved in.

Heavy iron equipment stored on the floor above appeared to have caused the collapse.

Three bodies were pulled from the wreckage and seven people were injured.

Rescuers combed through rubble for several hours and after clearing the site said that nobody else was trapped inside.

A local official said an initial investigation showed the ceiling that collapsed was poorly built and lacked the proper building materials to support heavy weight.

A trade union spokesman identified the factory as a Taiwanese-owned operation called Wing Star that produces trainers for Asics.

He said shoes made at the factory were imported to the United States and Europe.

An Asics spokeswoman in Tokyo confirmed the factory was contracted to make Asics running shoes.

She said the company was trying to determine what happened.

She said she did not have information on the last time the building structure had been inspected but added, "we want the highest priority to be placed on saving lives".

The factory complex, which opened about a year ago, consists of several buildings and employs about 7,000 people.

The structure where the collapse occurred was mainly used as a storage warehouse for shoe-production equipment but had a small work area for about two dozen people.

The garment industry is Cambodia's biggest export earner, employing about 500,000 people in more than 500 garment and shoe factories.

The accident comes about three weeks after a building collapse in Bangladesh killed 1,127 people in the global garment industry's deadliest disaster.

"This shows that the problem is not only isolated to Bangladesh, and that companies (elsewhere) are trying to drive prices down by taking shortcuts on workers' safety," said Phil Robertson of Human Rights Watch.