The Ministry of Manpower says the accident occurred on Monday on a jackup rig being built by Jurong Shipyard Pte. Ltd.
Jackup rigs are used for oil exploration and consist of a platform on three or four legs that can be raised or lowered.
A shipyard spokesman says the workers were testing the rig but one of the legs failed to operate, causing it to tilt to one side.
He says the injured workers were taken to hospitals and 53 were later discharged. One was in critical condition.
An investigation of the accident is continuing.
Jurong Shipyard is a subsidiary of offshore engineering group Sembcorp Marine Ltd.