The crews of hundreds of ocean-going yachts fear being stranded in the Pacific islands during cyclone season with usual safe havens in New Zealand and Australia closed because of Covid-19 travel restrictions.

Traditionally yachts sail south to escape the storm season but because of strict coronavirus protocols, the borders of both countries remain closed to all but their own nationals.

Representatives of the sailors have been lobbying both governments.

They have now gone public, claiming that a recent decision by New Zealand not to include cyclone refuge as a humanitarian ground allowing an exemption to Covid-19 entry restrictions put hundreds of people on an estimated 300 boats at risk.

John Martin, of umbrella group Sail South Pacific, said the bulk of the boats were in French Polynesia, 18 to 25 days of sailing from New Zealand.

Sail South Pacific and the Ocean Cruising Club have asked the New Zealand government to reconsider. The health ministry was alerted in April and in June the ministry said there would be an exemption process, raising the sailors’ hopes.

But according to the ministry of health website, foreign vessels are not permitted to arrive in the country unless they have an exemption.

Exemptions can be given if there was a substantial economic benefit to New Zealand, such as for superyachts undergoing repair or upgrades.

Smaller yachts require exemption on humanitarian grounds but this does not include refuge from storm season, according to the ministry website.

“For clarity, humanitarian reasons or other compelling needs would be unlikely to include situations relating solely to financial loss, or to vessels travelling primarily for pleasure or convenience such as tourists or ‘wintering over’,” the website reads.

“People in vessels travelling to New Zealand to ‘winter over’ (eg to avoid hurricane/cyclone season in the Pacific) may have other genuine humanitarian reasons or other compelling needs for coming, which would need to be demonstrated in order for these vessels to qualify for an exemption.”

Martin, who has been working with marinas in the north of New Zealand to ensure self-isolation aboard could be undertaken safely and to stagger arrivals, said the late decision not to grant exemption for sailors seeking safe haven from storm season was “very frustrating” and has left many “distraught”.

Sailors have few alternatives. Under its ‘Blue Lanes’ policy, Fiji allows yachts and pleasure craft to sail into Port Denarau and, after completing Covid-19 safety requirements, those aboard can go ashore. Prime Minister Frank Bainimarama has pushed the ‘Blues Lanes’ policy, inviting billionaires to “escape the pandemic in paradise”.

But Martin said spaces in Fiji’s cyclone-safe Denarau and Vuda marinas were limited and could not accommodate anywhere near the number of yachts seeking shelter.

Australia’s border, like New Zealand’s, is closed to all but nationals and those granted exemptions. While Australia does not appear to have issued as explicit a refusal as New Zealand, it had yet to give any the green light.

“To date, all foreign-flagged boats that have applied for an exemption to enter Australia’s waters have been denied,” Guy Chester, Ocean Cruising Club roving rear commodore told the Guardian.

He added that Australian authorities had officially said that yachts could apply for exemptions, but in practice, none were being approved.

New Zealand’s ministry of health, and the Australian border force – the two agencies that would be required to approve any exemptions – have been approached for comment.

New Zealand prime minister Jacinda Ardernon Monday said the government had to make sure it was being consistent. “What we didn’t want to create was a situation where you can’t come in by plane but you can, perhaps, come in by boat,” she told The AM Show.

“That’s one of the issues that’s been at play, however – it is cyclone season and we do need to make sure we’re balancing that principled approach with also making sure that we have health and safety in mind for those who might be in our region.”

Ardern said she would speak to her ministers about “just how we can accommodate those two competing issues”.

“We need to take a look at these particular seasonal circumstances.”