The Maritime Union is floating the idea of an "oceanic" shipping bubble to protect against Covid-19, after a third coronavirus-riddled ship docked in New Zealand.
Nine infected crew members are isolating aboard the Mattina in Bluff. It is the third vessel to dock in New Zealand after crew tested positive for the virus.
Mattina, a container ship sailing from Indonesia, had recently berthed in Fremantle, Western Australia.
Maritime Union national secretary Craig Harrison said it might be time to rethink port border measures.
He told First Up putting rules around a shipping bubble with certain countries and ensuring everyone was vaccinated could keep the virus at bay.
He said hundreds of ships had been to the country since the pandemic began but there were no incidents like the recent ones.
Crew from the Spanish-flagged vessels Viking Bay and Playa Zahara also tested positive for the virus in the last week. They are being cared for in Wellington and Christchurch respectively.
"With the way the virus is moving now, becoming more infectious, maybe we should be reviewing what our measures were and see if we have to do a bit more to manage the risk as the pandemic keeps on spreading."
Harrison said the government had the right to ask international shipping companies - especially the big ones like Maersk, MSC, CMA CGM and COSCO - docking here if their crews were vaccinated and regularly tested.
"Imagine if we hadn't taken them and they decided to go to one of our Pacific neighbours, the tragic impact that would have. We've done the right thing and pulled them in but the risk is still out there."
He said the governments of where the shipping vessels were from should also be asked about mitigation measures, vaccinations and testing routines.
"The question is why are those vessels down here fishing anyway to start with? We shouldn't be seen as an easy touch."
Harrison said shipping companies were making millions of dollars and needed to be questioned why the crew were not vaccinated.
In Australia, another ship that departed Indonesia, the BBC California ship has docked in Fremantle after crew tested positive for Covid-19.
Of the 14 people on board, 10 are infected.
The BBC California crew will remain on the ship isolated in their rooms until further notice.
- RNZ / ABC