The next high tide is at 3.42pm (Fiji Time) in Lautoka and 3.45pm (Fiji Time) in Suva.
National Disaster Management Director Vasiti Soko said the periods of heavy rain are expected to persist throughout the country until Sunday.
She said as of this morning, most river levels have already reached or are above their warning level.
Continuous heavy rain is expected to cause the rivers to burst their banks.
Soko said rivers that have already burst their banks are Rakiraki, (Nasivi) Tavua, Ba and Vitogo located on the main island of Viti Levu.