NUKU'ALOFA, Tonga, Feb 2, 2022 (BSS/AFP) - Volcano-devastated Tonga will close its borders Wednesday after Covid-19 was detected in the previously virus-free Pacific kingdom as it struggles to recover from last month's deadly disaster, officials said.

Prime Minister Siaosi Sovaleni said two men tested positive this week in the capital Nuku'alofa and were in isolation.

He said the men had been working in the city's port, where humanitarian aid has been pouring in from around the globe since the January 15 eruption.

"The most important issue at the moment is to slow down and stop those who have been affected," Sovaleni said during a national address late Tuesday.

"That's the reason for our national lockdown... no boat will be allowed to go from one island to another, no more (domestic) aeroplane flights."

Sovaleni said Tonga would close its borders from 6:00 pm (0500 GMT) Wednesday, with the situation reviewed every 48 hours.

Tonga first closed its borders in early 2020 as the coronavirus pandemic swept the globe.

Since then, the nation of 100,000 had recorded just one case of Covid-19, a man who returned from New Zealand in October last year and has since fully recovered.

However, the devastating blast from the Hunga Tonga-Hunga Ha'apai volcano, which lies about 65 kilometres (40 miles) north of Nuku'alofa, created what the Tongan government described as an "unprecedented disaster".

The volcanic blast, one of the biggest recorded in decades, generated massive tsunami waves and blanketed the island nation in toxic ash, claiming three lives.

In response, Australia, New Zealand, the United States, China, France, Fiji and Britain have sent ships carrying aid including drinking water, medical supplies and engineering equipment.

All of the deliveries were to be handled using strict "no-contact" protocols in a bid to keep the virus at bay, including leaving goods in isolation for three days before they are handled by Tongans.

Sovaleni did not reveal which ship the affected men had been working with.

He said they were asymptomatic and double vaccinated, along with about 85 percent of Tonga's population.

Australia's HMAS Adelaide docked in Nuku'alofa to unload supplies last week, despite a coronavirus outbreak that infected more than 20 of its crew.

The Australian Defence Force did not respond to a request Wednesday for the ship's latest coronavirus numbers, but Australian broadcaster ABC reported cases had soared to more than 70.

A United Nations update late last week said drinking water remained Tonga's main challenge and about 1,500 people were still displaced.

Communications remain patchy after the eruption damaged an undersea cable that connects the country to the rest of the world.

Officials said a specialist cable repair ship was expected to arrive this week and would take at least two weeks to fix the damage.