A marine pilot connected to a container ship struck by Covid-19 - and now off the coast of Tauranga - has been linked to a taxi driver in Australia who has tested positive for Covid.
But it is still unknown how the pilot became infected, leaving open the possibility that the Rio de la Plata crew members infected him and might have still been infectious when the ship was berthed in the Port of Tauranga.
The pilot was in Queensland when he had contact with the ship in July, and tested positive for the Delta variant nine days later.
Covid-19 Response Minister Chris Hipkins said he didn't have the results of any genomic sequencing comparison between the crew members and the Queensland pilot, and was unsure whether it could be done given the time that has lapsed.
"There are a variety of different scenarios as to who could have infected who. I want them to investigate all of those, and not make any assumptions," Hipkins said.
"They're [the crew members are] asymptomatic. That certainly tells us something. What that tells us we don't quite know, but it certainly tells us something."
Professor Michael Baker has said that the lack of symptoms indicates that the crew members may not have been infectious.
Hipkins confirmed that 109 port worker test results had come back negative, and one was being redone. Only 72 workers had boarded the ship, but more had sought a test.
He added that it was still hard to say whether any mistakes had been made in giving very different instructions to the port workers over a short period of time.
It has been reported that the link between the Rio de la Plata and the Queensland pilot was known to the Port of Tauranga on Tuesday last week, before the Rio de la Plata berthed.
But the port workers were allowed to unload the cargo on Wednesday evening before an isolation order came from Customs later that night. They were then told on Thursday that the risk was low and they should return to work.
Hipkins said he was still trying to piece together who told what to whom, the role of the Health Ministry, Customs and the local medical officer of health, and whether Customs might have overridden health advice with the order to isolate on Wednesday.
"One of the things that I am a bit frustrated by is that some of the information does seem to have been late in being shared. I only found out about this on Sunday night, for example. I've got some questions there.
"I haven't had the clarity of information I'm looking for."
Pilot linked to taxi driver
Queensland health authorities have confirmed the infected pilot linked to the Rio de la Plata has the same Delta strain as a taxi driver in Cairns.
Australian health officials believe the unvaccinated taxi driver, aged in his 60s, caught the virus from the marine pilot who he drove to the Cairns Airport on July 26.
The pilot, however, is said to be fully vaccinated.
Three cases of Covid-19 - all within MIQ facilities - were reported in New Zealand during today's 1pm update. There were no community cases of Covid.
Two of the new cases in MIQ came from Singapore and arrived in New Zealand on August 5. They both tested positive for the virus on day three of routine testing, the ministry said in a statement released this afternoon. The third case arrived in the country on August 7 from Australia. They tested positive on day 1 of routine testing, the ministry said.
One more Covid test result is due back from more than 100 Tauranga port workers tested after being onboard the ship. The original result was inconclusive but is considered low risk, the ministry said.
The ministry said a decision about where the crew of the Rio De La Plata will be transferred would be made in coming days.
Port of Tauranga officials earlier acknowledged the stress and worry facing their port workers, saying: "Victim blaming and abuse is not helpful."
"Our primary concern is for the port worker - including our pilots - who have been put in a very stressful situation."
A statement released just after 11am said Port of Tauranga had not officially received any information from the Ministry of Health regarding the test results for staff who had come close to the Rio de la Plata.
They had only been advised informally that 109 negative tests had come back in this round of "urgent testing".
It is not known exactly how many staff members work specifically for Port of Tauranga, but officials say all of their frontline staff are vaccinated against Covid-19.
But there are dozens of companies that work on the port," the statement said.
"Vaccinations have been available at Port of Tauranga since March. But the border order making vaccination compulsory was only introduced on July 14."
Port of Tauranga said they strongly support vaccination and have provided information sessions and vaccination centres on site.
They are due to host two other vaccination clinics at the port over the next two weeks.
Officials said despite getting fully vaccinated against the virus, staff continued to carry out other precautions such as cleaning frequently, using personal protective equipment and physically distancing themselves from a ship's crew.
Regular Covid-19 testing was also carried out.
"These precautions were followed by all workers who boarded the Rio de la Plata last week. Port of Tauranga treats all vessels as if they have Covid-19 on board."
Port officials revealed more details showing what happened just before authorities realised the vessel was linked to a Covid positive case in Australia.
The ship was tied up at the Port of Tauranga for three days last week - from 6pm on Wednesday to 2pm Saturday.
The day before it was tied up at the port - on Tuesday - port officials received an alert from Maritime NZ saying the ship had been boarded two weeks before by an Australian pilot who had tested positive for Covid-19.
Despite that alert, Maritime NZ cleared the ship for pilot boarding, Port of Tauranga says.
A medical officer of health at the local public health unit also cleared the ship to berth.
"A Port of Tauranga pilot boarded the vessel at approximately 5pm on Wednesday and brought the ship in to the Tauranga Container Terminal.
"At about 9pm, Customs NZ unexpectedly shut down operations on the ship and the local public health unit advised Port of Tauranga that our pilot and the stevedores unloading the ship should go home and isolate while awaiting further instructions."
By Thursday morning, however, Government agencies and the public health unit are said to have advised port officials that operations could resume again on the vessel and that there was no need for workers to isolate.
The container terminal at Port of Tauranga is now operating at about 50 per cent capacity, until workers are formally advised they can return to work.
Some staff members are set to be re-tested today, however, the statement said.
Today's Covid update reported that the two pilots, one of whom brought the Rio De La Plata into port and the other who took it out, have both now been tested and have returned negative results (their results are included in the total reported above) and will remain in isolation for the balance of the 14 days post possible exposure.
The local public health unit, Toi Te Ora, has now confirmed that 72 port workers boarded the vessel while it was docked in Tauranga.
All 72 of these workers have been tested and all results are negative, with only the retest of the port worker currently outstanding, the update said.
"Some individuals may have an additional test to ensure they fall within the 72 hours threshold of when they were last on the ship.
"Initial reports of the numbers of port workers on the vessel also included individuals who were on the wharf but did not go onboard. Those individuals have also been tested out of an abundance of caution and those results are also negative.
"All ships coming to New Zealand from overseas are treated as if the ship has COVID on board and protocols are in place to manage these risks. The Ministry understands from local public health staff that all infection prevention controls, and PPE protocol, were followed by port workers who had contact with the ship during their duties."
The number of active cases in New Zealand now stands at 36. Since the start of the year, 116 historical cases of Covid-19 have been reported out of a total of 716 cases.
The seven day-rolling average of new cases found at the border stands at two.
The total number of confirmed cases of Covid-19 in New Zealand is now 2534.