At least nine of the 21 crew members on board a containership have tested positive for Covid-19 at a port in the south of New Zealand.

The Marshall Islands-flagged, 4,363-teu Mattina (built 2007) arrived at South Port New Zealand on Sunday evening with two crew members initially testing positive for the virus.

The results of additional tests of the remaining crew came back late Monday evening, confirming a further seven cases of Covid-19 on board the ship.

A South Port Pilot, who had been fully vaccinated against Covid-19, boarded the vessel and piloted it into the port in Bluff, near Invercargill, on Sunday evening.

“Strict protocols were followed to ensure the risk to the pilot was minimised," South Port said. "This included personal protective equipment and physical distancing requirements to ensure minimal interaction with the crew.”

The New Zealand government said no one else has been on or off the ship since it docked.

Authorities said Monday’s testing for Covid-19 took place on the gangway area and all appropriate protocols were followed by health staff, including PPE.

Local health officials are said to be working with other agencies to determine the next steps for the ship. In the meantime, the crew members remain on board the Mattina.

“The Mattina remains in quarantine in a secure area of the port, which is inaccessible to members of the public and fencing will be put up to further restrict access to the ship,” a government spokesman said.

The initial two crew members who tested positive for Covid-19, are said to have joined the ship in Singapore on 2 July after providing negative pre-departure tests.

Located in Bluff Harbour, at the southern tip of New Zealand’s South Island, South Port is New Zealand’s southernmost commercial deepwater port.