The system is forecast to swerve south of Rotuma tonight, before tracking close to a major town, Labasa, tomorrow as a category one or two cyclone.
The Fiji Meteorological Service said it was then likely to move close to Tonga's main islands as a category two over the weekend.
Heavy wind and rain warnings are now in force for much of Fiji, with coastal flooding also forecast for Rotuma.
Source:
RNZ Pacific