The ship, African Rook, left Geelong before September 20, and during its voyage the crew members were alerted to the fact they were primary close contacts of a COVID positive person.

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The 21 crew members were tested for COVID on arrival at Bell Bay, and have since returned negative tests.

Just days before the ship departed Geelong, a Victorian dock worker had worked alongside the crew and tested positive to COVID-19 shortly thereafter.

According to ship tracking information, African Rook first arrived at Devonport on September 19 before being diverted two hours later to the Bell Bay port where it arrived on September 25.

Tasmanian Public Health Deputy Director Dr Julie Graham said upon arrival in Devonport, "appropriate due diligence and risk assessment" was carried out and it was deemed Bell Bay was the best option for the 31 metre long cargo ship.

Dr Graham said the crew members would remain on board the ship until they had completed 14 days quarantine, due to be finished by October 1. And would be retested prior to the vessel being allowed to continue its journey.

"There is no risk to the Tasmanian community as the crew remained on board at all times and had no contact with members of the public," she said.

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