Napier Port is refusing to allow a ship with 21 close contacts of a port worker who tested positive for Covid-19 to dock, meaning the ship and crew could be forced to sail to Auckland.
The Ken Rei was due in port on Sunday to load logs but has been anchored off the coast since Sunday afternoon.
It is carrying 21 sailors, all of whom are considered close contacts of New Zealand's newest Covid-19 community case.
The male port worker, a marine electronics engineer from Auckland, who went to New Plymouth for work last week, tested positive for Covid-19 on October 16.
The man worked on the Ken Rei, which only operates in NZ waters and has a NZ-based crew.
The likely source of his infection is another ship, the Sofrana Surville, which is bound for Brisbane from Auckland and Noumea.
Director general of health Dr Ashley Bloomfield said at a press conference on Monday the crew of the Ken Rei were getting daily health checks via radio and none had been showing symptoms of Covid-19.
The people on the ship had not yet been tested and options were being looked at to facilitate this, including whether a vessel or helicopter could come out to the ship or if it could be sent to Auckland.
Napier Port did not want the ship to berth, Bloomfield said.
What to do if any of the 21 crew on the ship off Napier tested positive was still being worked through, he said.
The ship turning into a "petri dish" for Covid-19 was one of the considerations, he said, and crew members were trying to take precautions.
When asked about dealing with the ship, Bloomfield said "there is urgency".
But all crew members were asymptomatic, and anchoring off the coast at the moment was not causing any frustration while the next move was being resolved, he said.
The Health Ministry didn't have a preference about whether the ship docked in Napier or elsewhere, he said.
A Napier Port spokesperson on Monday confirmed that the ship remained offshore and had not been into Napier Port.
"Our position remains that the ship should stay anchored offshore. We will await further instructions and assist public health as necessary."
A Hawke's Bay DHB spokesperson said it continues to work closely with the Ministry of Health and port officials.
The Maritime Union of New Zealand said the new Covid case showed there was an "urgent need" for coastal shipping reform.
Union national secretary Joe Fleetwood said the union had repeatedly raised concerns about the risk of having international ships carry domestic freight.
He said nearly all domestic sea freight was carried by international ships running international crews who were not covered by New Zealand law - meaning "every single one" of NZ's ports is an international border point and "it puts our members and the public at risk".
"Other nations run a small number of international ports as hubs for their protected domestic sea freight which give them greater control of their border security and of their supply chains.
"There's a reason our international airports are limited to large sites that can resource strong border security, we should be doing the same with our ports."
He said there should be two in the North Island and two in the South Island, which would be "secure and safe points of entry for goods".
"All other cargo should be shifted by New Zealand-flagged vessels that operate under our law and are staffed by people from our team of five million."
Fleetwood said the union has been talking to the Government "for a while" about the issue and both Labour and the Greens have "repeatedly backed the need to strengthen New Zealand-flagged coastal shipping".
But Bloomfield said the current port measures were "very good" and included regular testing, including of those who accessed ships.
The workers were being tested fortnightly, and Bloomfield said one thing being looked at was whether such workers should be tested two to three days after finishing a long shift working on a ship.