The Fiji met office says tropical cyclone Winston has been upgraded to a category four system.
Cyclones Winston and Tatiana Photo: Vanuatu Meteorological Service
Cyclone Winston is expected to pass close to Vanuatu's southern islands of Tanna, Erromango and Aneityum.
The cyclone is moving at 12 kilometres an hour and intensifying.
Expect sustained winds of 166 kilometres an hour close to the centre, increasing to 185 kilometres an hour later today.
In Fiji, a flood alert remains in force for all low lying areas along Rakiraki river, including Rakiraki town.
Meanwhile, tropical cyclone Tatiana has now been downgraded to a category one system.
The cyclone is moving south at 15 kilometres an hour over the central Coral Sea and is about 1,030 kilometres east northeast of Yeppon, and 890 kilometres northeast of Sandy Cape.
On its current track it is expected to pass to the west of New Caledonia.
According to Australia's Bureau of Meteorology, tomorrow will bring unfavourable atmospheric conditions which should weaken the cyclone and see it transition into a deep subtropical low pressure system.