A tropical cyclone alert has been issued for the French Pacific islands of Wallis and Futuna.
The Met Service in Nadi says a tropical depression has formed and is now about 250 kilometres northeast of Wallis.
The system is intensifying and is expected to develop into a tropical cyclone in 12 to 24 hours.
Forecasters expect damaging gale force winds and periods of heavy rain and squally thunderstorns for Wallis, and wind increasing over the next 36-48 hours for Futuna.
And heavy rainfall is expected throughout the northern and central parts of Vanuatu over the next day.
The Vanuatu metservice is expecting looding is expected over low lying areas.
A marine wind warning has been issued for all open waters of the Vanuatu group.