Eight crew members are still missing at sea, a day after their barge capsized in Singapore waters.

Search and rescue operations continued on Thursday for those who were onboard the Mongolian-flagged vessel, Guo Liang 677, said the Maritime and Port Authority of Singapore.

MPA said it was alerted to the incident on Wednesday afternoon, which occurred about 7 nautical miles north of Horsburgh Lighthouse. Two of the vessel's crew members were rescued on Wednesday, one by a Police Coast Guard (PCG) patrol craft and the other by another vessel in the vicinity.

The first rescued crewmember is well and does not require medical attention, while the second one is said to have been brought to Malaysia.

It is believed there are 10 crew members, all Chinese nationals, onboard Guo Liang 677. The Chinese Embassy in Singapore has been kept informed.

As of 7pm on Thursday, the ongoing search and rescue operations involved helicopters, a maritime patrol aircraft from the Republic of Singapore Air Force, three patrol vessels from the Republic of Singapore Navy, two PCG patrol craft, divers and two diving support vessels from Resolve Salvage & Fire (Asia), and 14 passing commercial vessels.