Tropical cyclone Thomas has intensified overnight, and is expected to intensify further as it heads for Fiji.
The cyclone is one of two named in the past 24 hours, and formed from a tropical depression north of Wallis and Futuna.
A senior forecaster for Fiji's metservice, Matt Boterhoven, says it is currently about 165 nautical miles northwest of Wallis, and is expected to move in a southwesterly direction over the next 24 hours, and then a southerly direction.
"We've put an alert out for Fiji from Sunday afternoon and we could see it push into the Fiji group from Monday. Tropical cyclone Thomas is now a category two system and over the next 24-48 hours we expect it to increase to a category three and a category four system."
Matt Boterhoven says Wallis can expect gust to up to 60 knots, with heavy rain, sually thunderstorms, and heavy swells.
Samoa's met service has issued a gale watch for the west side of Savaii, and a high wind advisory for all highlands and nothern coastal areas.
Meanwhile, Tropical Cyclone Ului is currently 150 nautical miles Northwest of Vanuatu's northern islands.
David Gibson, from Vanuatu's metservice says heavy rainfall and flooding will continue to affect the northern and parts of the central islands.
The system is still in close proximity to the Nothern Islands. We get a lot of rain, and so flooding is possible over low lying areas and also seas are very rough at the moment, up to 35 knots in the open waters, so boats, open vessels, are still advised not to go out to sea at this time. It is heading towards the Solomon Islands and is likely to intensify because it is towards the open waters.
David Gibson says warnings are likely to remain in place for most of today.