Fiji's main tourist town, Nadi, has come to a standstill under one metre of flood water with the levels rising.
Traffic has been disturbed and people are wading through muddy waters trying to find their way out of the town.
The mayor of Nadi, Salesh Mubalior, says businesses and residents have been evacuated.
"All the shops around the main CBD have been closed and people are being evacuated and leaving the town. the worst scenario is that both ends of town are being flooded in and people can hardly move out of town."
Heavy rain is continuing with the situation expected to worsen because of high tide.
The military is helping police maintain order in the town and both security forces are ready to help in any evacuation.
Disaster authorities have set up four evacuation centres in the town.
The Nadi Weather Office is predicting more rain this afternoon and tonight before it begins easing by about Wednesday