Nuku'alofa: Tonga declared a state of emergency Monday as the Pacific island kingdom braces for a direct hit by a powerful cyclone that is threatening to become a Category Five superstorm.
Severe Tropical Cyclone Gita has already created havoc in neighbouring Samoa and is gathering pace as it approaches Tonga.
Acting Prime Minister Semisi Sika issued a nationwide alert, saying he was "satisfied that an emergency is happening or is about to happen".
The Fiji Meteorological Service predicted Gita will become a Category Five storm, the top of the scale, before reaching Tonga Monday night.
It is already packing gusts of 275 kmh (170 mph) as it sits off the east coast of the country's most populous island Tongatapu.
Tonga's Fua'amotu Weather Forecasting Centre warned residents could expect "very destructive hurricane force winds".
Gita slammed into Samoa overnight Friday, forcing the evacuation of some 200 people and causing widespread flooding, leaving many without power.
Philip Duncan, chief forecaster at New Zealand's Weather Watch service, said that current modelling showed Gita was lining up a direct hit on Tongatapu.
"That's a very serious situation, the capital (Nuku'alofa) is there, there's over 75,000 people," he said.
"It's pretty rare to see the perfect circle, the centre of that storm, going right over the top of such a small island."
'Major damage' feared
Duncan said the cyclone could cause major damage even if it remained offshore.
"If it moves just a little bit north or south it may not make technical landfall but it's severe weather, winds up to 230 kmh, waves over 10 metres at sea and a storm surge over a metre on top of that," he said.
Truckloads of troops were out helping people batten down as Nuku'alofa prepared for the cyclone and evacuation centres were opened across the kingdom.
The information ministry advised anyone considering moving to the shelters to leave early, saying travel would not be possible when the eye of the storm passes over.
Otherwise people should stay at home and ride out the wild weather, it said.
"Every family should have an emergency kit packed in their homes," it said.
"Everyone should be mindful of what might cause damage within their homes such as large trees that can potentially damage a house."
Tonga Meteorological Service director Ofa Fa'anunu said Gita would be one of the strongest cyclones to ever hit the kingdom.
"We are looking at major structural damage," he warned, pointing out that the low-lying capital was particularly vulnerable to storm surges.
Cyclones are common in the Pacific at this time of year, with top-of-the-scale Category Five systems proving highly destructive when they make landfall.
Cyclone Winston killed 44 people in Fiji in 2016, and Cyclone Pam claimed 11 lives and damaged 65,000 homes in Vanuatu in 2015.
Another Category Five storm, Cyclone Ian, hit Tonga's sparsely-populated Ha'apai islands in 2014, causing extensive damage and leaving thousands homeless. (AFP)