A crew member on-board a ship off the West Australian coast who tested positive for COVID-19 is in a stable condition in hospital.

The man, aged in his 50s, became ill on April 8 while on-board bulk carrier AquaGenie off the coast of Karratha.

A rapid test was performed on-board the ship, then a smaller ship was sent to retrieve the sick man on Sunday.

The man, from the Philippines, was taken to Karratha Health Campus and was later transferred to Royal Perth Hospital where he remains in a dedicated isolation ward with a pressure room.

West Australian Health Minister Roger Cook told reporters the man was in a stable condition and none of the other 23 crew members were unwell.

“Obviously, if you’ve got one positive case on-board, it’s very likely or possible that you can have more than one,” he said.

Echoing comments made by Premier Mark McGowan on Monday, Mr Cook said the state’s preference was for the vessel to sail away and not come into a West Australian port.

“With any vessel that comes into West Australian waters, we have to put people on-board – pilots, people of that nature, agricultural workers and so on,” Mr Cook said.

“While the actual interaction between the crew and portside workers is fairly limited, obviously it represents a risk, and we believe it’s an unacceptable risk.”

The bulk ore carrier had most recently docked at Chinese ports.

“Obviously, we have got a responsibility and obligation, both moral and legal, to assist any vessel that’s in distress, and that’s why we’ve assisted in the case of this crew member,” Mr Cook said.

“We are continuing to monitor the health of all the other crew members, and I’m continuing to work with the ship’s captain.

“But let us be clear, we do not want that ship to tie up – we believe that’s an unacceptable risk.”

Asked why it took so long for the public to become aware of the incident, Mr Cook said it was a commonwealth matter.