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.

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

A shipyard worker said he saw plumes of white and orange smoke after the explosion.

"I heard a very loud pong sound," the Chinese national told The Straits Times. "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 injured are foreigners.

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

Investigations were underway to determine where the fire started.

Among the injured was Ustin Massappa, a 35-year-old Indonesian national pierced by glass shards blown out from the ship's windows.

He told the newspaper there were about 20 shipyard workers on board along with the crew. He immediately ordered the electricity supply to be turned off.

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. (dpa)