Singapore  - An explosion rocked a Belize-registered ship in the final stages of repair at a Singapore dock, injuring 15 crew members and workers on board, officials said Monday.

A flash fire broke out Sunday in the 50-metre-long Rainbow Star, which had been berthed at Kreuz Shipbuilding & Engineering in Tuas Crescent for nearly three months.

Six workers suffered severe burns with four in intensive care. One suffered burns over 90 per cent of his body.

The other nine were treated for smoke inhalation.

The incident is under investigation.

A shipyard worker told The Straits Times that he saw plumes of white and orange smoke after the explosion.

"I heard a very loud pong sound," the Chinese national said. "The whole boat was covered in smoke."

"Those on board started shouting, 'Run! Run!," he said, noting the smoke was pungent and stung.

All 15 of the injured are foreigners.

The Ministry of Manpower issued a stop-work order on all painting jobs at Kreuz.

The Civil Defence Force said the flames were confined to the 20 metre-by-5-metre bridge.

The Rainbow Star had been scheduled to sail for the Indonesian island of Batam this week.

"The engine was tested last week, said the business development manager of Orchid Star, which owns the Rainbow Star. "We are all shocked." (dpa)