Tongan Prime Minister Pohiva Tuionetoa warned that residents on the country's main island Tongatapu faced a possible lockdown next week after recording its first case of COVID-19.
The tiny Pacific kingdom had been among only a handful of countries to escape the virus so far, and the infection was detected in a person in managed isolation after returning to Tonga on a repatriation flight from New Zealand.
"The reason the lockdown won't happen this weekend is because I have been advised that the virus will take more than three days to develop in someone who catches it before they become contagious," Dr Tuionetoa said.
"We should use this time to get ready in case more people are confirmed they have the virus."
Most of Tonga's population of 106,000 live on Tongatapu, and fewer than a third have been double vaccinated against COVID-19.
Health officials said the person who tested positive had received their second jab in mid-October.
The repatriation flight included members of Tonga's Olympic team who had been stranded in Christchurch since the Tokyo Games. The athletes were double vaccinated before they departed for the Olympics.
New Zealand's health ministry confirmed the infected person had tested negative before the flight left Christchurch, where there are only four known cases of COVID-19, all of them in the same household.
