The Maritime Union says a Covid alarm aboard a vessel in the Port of Tauranga is a reminder that strict processes at ports are essential to protect New Zealand from exposure.

On Tuesday, the Port received an alert from Maritime NZ that a container ship at anchor, the Rio de la Plata, had been boarded two weeks ago by an Australian pilot, who recently tested positive for Covid-19.

Maritime NZ subsequently cleared the ship for pilot boarding.

The ship was also cleared to berth by the Medical Officer of Health at Toi Te Ora Public Health as part of the normal free pratique process, says a spokesperson for the Port of Tauranga.

'At about 9pm on Wednesday, 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.

'Government agencies have clarified the situation and the Public Health Unit has advised us that operations can resume on the vessel and there is no need for workers to isolate.” Read more here.

Maritime Union of New Zealand National Secretary Craig Harrison says the incident aboard the Rio de la Plata did not directly affect Maritime Union members.

He says there had been some confusion about the status of the vessel and its crew, and communication may have to be improved, but any false alarms were preferable to exposure to Covid.

Harrison says it's important that stevedores and port companies continue to ensure strict protocols are followed and PPE gear is used, as this had been successful so far.

He says the Maritime Union wants to see more proactive measures including public health staff visiting ports and having conversations with workers about the importance of vaccination.