Viking Orion first docked in New Zealand in mid-December.
RNZ reports Biosecurity New Zealand environmental health manager Paul Hallett said approved ports can manage risk better than special marine environments, like Fiordland.
"Approved ports have regular surveillance, our teams are based there, and ships stick to regular vessel pathways," he said.
Despite the restricted status, Viking Orion still visited commercial ports in Dunedin, Christchurch, Wellington, Napier, Tauranga and Auckland.
But Hallett said the ship was given a final departure date.