Search and rescue operations are underway for the man who went missing after an accident at sea involving a ferry and a coaster craft on Saturday morning.

The Indonesian-registered coaster craft, Budi Jasa 18, sunk in the West Keppel Fairway, after it collided with the Sea Hawk, which was ferrying about 200 passengers from Pasir Panjang Ferry Terminal to Pulau Bukom.

The Maritime and Port Authority of Singapore (MPA), responding to queries from The Straits Times, said five crew members on board the smaller coaster craft have been rescued but one was reported missing.

"MPA is currently co-ordinating the search and rescue operation, involving two MPA and two Police Coast Guard craft," said the authority in a statement on Saturday.

"Divers have also been activated. Rescue efforts with the Police Coast Guard after the incident was reported at 6.25am."

Eight passengers from the Sea Hawk suffered injuries, of which five were sent to Bukom Clinic to receive medical treatment for cuts and abrasions, while three others were sent to Alexandra Hospital.

The MPA said it has issued navigational broadcasts to vessels in the vicinity to keep clear of the SAR area and to report any sighting of the missing person. Port operations are unaffected.

MPA is investigating the incident.