Disaster authorities in Tonga say they are keeping a close eye on cyclone Winston, which is expected to strengthen before entering the country's waters later today.
The category two cyclone is currently near Fiji's southern Lau group, with winds of up to 130 kilometres an hour at its centre.
The Fiji Metservice said there was still some chance the cyclone might intensify into a category three within the next 48 to 72 hours, as it moves towards Tonga's Vava'u and Ha'apai island groups.
Tonga's National Emergency Management Office director Leveni 'Aho said authorities were monitoring it very closely and people across the country should be prepared.
"The fact it's going back up is an unusual event - from the south to north. So it might affect most of Tonga including Tongatapu here and Ha'apai and maybe even heading north to Vava'u as well," he said.