The fishing vessel Viking Bay, with two crew members who have tested positive for Covid-19, will dock at Queens Wharf in Wellington tomorrow.
Customs has confirmed plans are in place for the safe and coordinated return of the Viking Bay to New Zealand.
Perimeter fencing will cordon off the area where the vessel docks, to remove public access, Customs said in a statement.
Authorities will step up security at the wharf and on-water patrols will be on duty.
The 20 crew members will undergo comprehensive health checks, including testing.
Most will be taken to a managed isolation and quarantine facility to complete at least 14 days, while a small number will complete managed isolation on board.
Customs' group manager maritime Stephen Waugh said there will be a very low public health risk.
"The crew will be transported at a time that will minimise the risk of coming into contact with members of the public," he said.
"Customs will maintain presence at the port throughout the operation, with the support of additional security personnel, and the Police Maritime Unit maintaining watch over the water."
All Government and CentrePort staff who interact with the vessel or crew are vaccinated, and will work in line with health and safety protocols, Customs said.
Those who remain on board will receive daily health checks and the boat will undergo a deep clean at the end of the isolation period.
The two infected mariners arrived in Auckland last Monday and were driven to New Plymouth to join the ship.
Meanwhile, there are no new cases of Covid-19 in the community and three new cases in managed isolation and quarantine.
The returnees arrived from the Malaysia, Russia and the United Kingdom.