A heavy rain alert is now in force for the whole of Fiji.

The Nadi Weather Office says a trough of low pressure lies over Viti Levu.

Associated cloud bands with rains are affecting Viti Levu, Kadavu nearby smaller islands, and Vanua Levu.

The weather office says if the current conditions persist, the low-pressure system could develop into a tropical depression by Thursday.

If this were to occur, the tropical depression would be located north-northwest of Fiji.

Persistent heavy rain over the next few days could result in flash flooding of low lying areas.