The whole of Fiji's Navua town and surrounding settlements about 40 kilometres west of Suva are under 2 metres of water.
This follows heavy rain of up to 100 millimetres an hour over many parts of Fiji last night and this morning.
Police and the military are helping in the rescue and evacuation of hundreds of people cut off by flood waters in Navua.
But some people are refusing to leave because of fears of looting.
The only access to many homes is now by boat.
Patients at Navua hospital have been evacuated to an already overcrowded Suva Hospital where the maternity ward remains closed because of water damage.
The Queens Highway between Suva and Nadi is cut off in many places because of flooding.
The Kings Highway is also closed, leaving Suva and southern Viti Levu isolated from the west.
The Rewa River at Nausori is rising and about to burst its banks.
Renewed flooding has been reported from Korovou town and surrounding areas in Tailevu with most roads closed.
Most schools have been closed and many are being prepared for use as evacuation shelters for people forced to abandon their homes.