The northwest of Fiji's Viti Levu is struggling as rain that has fallen for several days continues.
There has been extensive flooding, some schools have been closed and some residents have been forced to move to evacuation shelters.
Another storm system is forecast for later this week.
In Tonga a heavy rain warning is in force with the Vava'u and the Ha'apai island groups expected to get the brunt of the bad weather from Thursday night.
Radio Tonga reports some schools were closed on Wednesday due to flooding concerns.
There was also flooding earlier this week in Solomon Islands and forecasters there say more bad weather is due later this week.
Heavy rain in New Caledonia has cut roads on the main island's east coast, with the region warned to expect up to 150 millimetres of rain today.
Unusually heavy rain along the east coast in November caused floods and landslides, killing eight people.
The rain around the region is due to a series of slow moving weather systems.
Photo: Supplied/ CARE Flooding in Rakiraki, Fiji.