On Monday a 41-year old Chinese crew member fell from a ladder on the Singapore-registered ship Cape Splendour, which was anchored at Port Hedland.
The man was attempting to clear entangled fishing lines when he fell.
Fellow crew members tried to rescue the man, but soon lost sight of him.
“He tried to swim to them, but the tides were too strong for him,” a water police spokesman told AAP.
The spokesman said the man was swept 450 metres away within 10 minutes.
The search was suspended at 2pm on Wednesday.