WA Health is monitoring a COVID-riddled ship which is docked in Fremantle, after nearly all of its crew tested positive to coronavirus.

Premier Mark McGowan confirmed 20 of the 22 seafarers from the Ken Hou have tested positive, but says none of them will be coming off the ship at this stage.

“For now, the vessel will remain berthed at Fremantle Port with all positive crew members remaining on-board and their health status monitored daily,” Mr McGowan said.

“WA Health is working closely with the captain, shipping agent, vessel owner, WA Police, Fremantle Ports and Commonwealth agencies to manage the vessel and crew, with plans underway to move the remaining two negative crew members to hotel quarantine.