A Heavy Rain Alert is now in force for Vanua Levu, Taveuni and nearby smaller islands, Lomaiviti, Central and Northern Lau group.
The Nadi Weather Office says a trough of low pressure with cloud and showers remain slow moving over the southern and eastern parts of the group.
Another low pressure system with cloud, showers and rain lies just to the northeast of Fiji.
It is gradually moving southwards and expected to drift through the group from later today until Saturday.
The rain is expected to affect the country until Saturday.
Meanwhile, a Severe Thunderstorm Warning is now in force for the northern half of Viti Levu (from Nadi through Rakiraki to Korovou) and the eastern half of Vanua Levu (from Northern Bua through Labasa to Udu Point, and Wailevu through Savusavu to Saqani, including Natewa).