A body was retrieved from the waters off Jurong on Friday morning. It is believed to be that of one of three men missing after Tuesday's tugboat fire.
It was found in waters a few metres off Tanoto Shipyard, the Maritime and Port Authority (MPA) said yesterday.
Police are investigating the discovery and treating it as an unnatural death.
A spokesman for the MPA said that suspected human remains were also recovered on board a half-sunken vessel last night. These will be sent for forensic investigations.
The blaze broke out at 9pm on four tugboats berthed alongside each other. It took the Singapore Civil Defence Force nine hours to put out the fire.
Reports said that oil from one of the vessels had leaked into the water, feeding the flames.
Another four crewmen, all believed to be foreigners, were injured.
Two were still in critical condition last night at the Singapore General Hospital. They suffered at least 30 per cent burns.
The other two are warded at the National University Hospital. They are said to be in a stable condition.
An ongoing search-and-rescue mission is being coordinated by the MPA.
Two vessels, one from the MPA and one from the Police Coast Guard, have been sent out to continue the search for the missing men.
Meanwhile, Tanoto Shipyard, which repairs vessels, has been instructed by the Manpower Ministry to stop all work while investigations are ongoing.