The Fiji Meteorological Services says a heavy rain warning that remains in force the Northern Division and Northern Lau Group is now in force for the rest of the Fiji Group.
The weather office says Tropical Disturbance TD12F which lies to the west of Vanuatu is expected to gradually drift east-southeast.
It says the associated trough of low pressure is gradually approaching the group from the northwest and rain developing in the afternoon and becoming frequent and heavy from later today.
A flash flood warning remains in force for all flash flood-prone areas, small streams and low-lying areas of Vanua Levu and is now in force for all flash flood-prone areas, small streams and low-lying areas of Viti Levu.
It adds that gusty winds are possible during heavy falls and thunderstorms.