Premier Mark McGowan admits mistakes were made in handling the Al Kuwait livestock carrier which docked in Fremantle last Friday, conceding he didn't have all the facts when he took aim at federal agencies.

The WA government was forced to back-pedal on Wednesday after complaining the federal Department of Agriculture didn't advise the state that three crew had fevers before it docked.

But an email was sent to the general inbox of WA's Public Health Emergency Operations Centre, and state health officials didn't board the vessel and start testing until Monday.

The state's health minister insisted, however, there is no risk to the public as the six crew members who tested positive are in quarantine in a Perth hotel and did not enter the community and no-one else from the ship has been allowed to disembark.

The seven quarantine and port workers who went on board were all wearing personal protective equipment, but two had been deemed close contacts and are isolating, Roger Cook said.

Mr McGowan said no further cases had been confirmed on the vessel and 27 of the 42 multinational crew remaining on board would be removed as a precaution and put in a hotel, while the remaining 15 will stay on board as skeleton crew and monitored daily.

He admitted there were gaps in communication between federal and state authorities.

"Unfortunately, yesterday I wasn't provided with some information, which meant the full picture was not clear," he said on Wednesday.The email said there were no COVID-19 concerns but he was disappointed nevertheless that it had not raised red flags in the state health department.

Also, the federal department should have done more than just send an email.

"There clearly have been some errors all round," Mr McGowan said.

"We have to learn from our mistakes and move forward."

Mr Cook said sending the email to a general inbox was inappropriate.

Federal Agriculture Minister David Littleproud earlier moved to allay concerns for those who boarded wearing protective equipment.

"Everyone who has come into contact with the Al Kuwait has undertaken that," Mr Littleproud said.

He also insisted the situation was handled correctly.

"I have asked my department to go back and double-check and triple-check to make sure that every protocol has been adhered to," he said.

"But on the face of it, we believe that every protocol was in line with the COVID protocols that have been put in place."

Meanwhile, Prime Minister Scott Morrison launched a pre-emptive strike against calls to shut down the live export industry during the global pandemic.

"We've got the systems in place and they can be managed and they can be protected," he told Sky News.

Australian Associated Press