NUKU'ALOFA, Tonga -- Tonga's main island entered a week-long lockdown Tuesday just days after recording its first case of Covid-19, ending the Pacific nation's run as one of the last virus-free places in the world.

Prime Minister Pohiva Tuionetoa said the island of Tongatapu, which includes the capital Nuku'alofa, would remain in lockdown until next Tuesday.

Tuionetoa told reporters late Monday that the stay-at-home order was to "ensure the safety and health of our people ... to prevent or minimise the spread of Covid-19 within the kingdom of Tonga".

Tonga's first case was detected last week when a man who arrived on a repatriation flight from the New Zealand city of Christchurch tested positive.

The man, who was fully vaccinated, and another 214 people who were on the flight had been in isolation since landing and the health department said no community transmission had been found on the island.

The remote Pacific kingdom, about 1,800 kilometres (1,100 miles) northeast of New Zealand, had been among only a handful of countries to escape the virus that has affected billions worldwide and claimed nearly five million lives.

Only about a third of Tonga's population of 106,000, most of whom live on Tongatapu, have been double vaccinated against Covid-19.

But news that the first case had been detected in managed isolation prompted thousands to rush to get vaccinated.