"We're very concerned... and disappointed." Perth sees 'evolving' outbreak of COVID-19 cases.

Six crew members from a live export ship off Perth have tested positive for COVID-19, taking Western Australia’s total cases to 570.

It’s believed Fremantle port workers may have been exposed to COVID-19 when they boarded an infected live export ship that had apparently been cleared by a federal department to dock, despite knowing some of the crew were ill.

The Al Kuwait arrived on Friday after sailing from the United Arab Emirates and six of the 48 multinational crew have since tested positive.

According to Western Australian Police Commissioner Chris Dawson, a report was submitted to the federal Department of Agriculture, Water and the Environment advising some of the crew were sick on Wednesday.

But the Fremantle Port Authority only found out after up to half a dozen local workers boarded the ship, Dawson said.

WA Premier Mark McGowan says they are being isolated and contact tracing is under way.

McGowan said he doesn’t want to “point fingers at this point in time” but state authorities are working to find out what went wrong.

“We’re very concerned and to a degree, disappointed,” he said on Tuesday.

“Clearly, if there’s cases of people reporting high temperatures on board … red flags should be raised.

“So I just say to everyone involved, in particular the Commonwealth agencies that knew about this, they need to be on guard and be alert.”

He said the men who tested positive were being quarantined at a Perth hotel while the remaining 42 crew members appeared well and were being kept on board.

They would be monitored and given health assessments as required.

“This is a fast evolving situation. But I suspect it is probably more than likely that more crew members may become infected with the virus,” McGowan said.

Commissioner Dawson says he has been assured none of the crew disembarked.

McGowan said the state government wanted the ship to set sail as soon as possible, but it needed to be cleaned first.

Dawson suggested the federal agriculture department should do the fumigation, saying: “The Commonwealth have responsibilities here.”

Border Force said it completed all customs and immigration related clearances, but received no reports of illness on board the vessel on the day of or prior to its arrival in port.

The six new cases bring the number of active cases in WA to 10 after a Victorian family returned from Qatar with the disease on May 17.

Those four cases were confirmed on Monday, ending a streak of zero case days.

The family has been quarantining in a hotel since arriving.

“This situation again highlights that we are not free from this virus,” WA Health Minister Roger Cook said.

“There are still people getting sick and we are still at risk.

“We cannot be careful enough.”

The state government remains adamant the interstate border will remain closed for months.

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