A Heavy Rain Alert is now in force for Viti Levu, Yasawa and Mamanuca Groups, Kadavu and nearby smaller islands, and Lomaiviti and Southern Lau.
Localised heavy falls could lead to flash flooding in low-lying and flood-prone areas.
The Nadi Weather Office says a trough of low pressure is expected to approach the group from the west and affect parts of Fiji from late tomorrow.
Rain is likely to be significant in the afternoon, overnight or early morning.
There is a possibility of clear skies or sunny breaks in between the rain bands, especially during the early part of tomorrow.
