Fiji's Western Division needs to be declared a disaster zone according to the Fiji National Federation Party leader Biman Prasad.
Professor Prasad said initial assessments by his team showed the level of flood damage was worse than that of previous floods.
He said the damage was massive and the government should consider rehabilitation packages for people who are now worse off.
"To have a very good co-ordinated efficient and effective relief effort, the government needs to declare that area as a disaster area so that proper assessments and relief efforts and proper rehabilitation efforts can be put in place."
The deputy opposition leader estimated millions of dollars in damage to homes, crops, businesses and other infrastructure in the worst affected areas of Lautoka, Nadi, Rakiraki and Ba.
Constant threat
Fiji's prime minister Frank Bainimarama said the cyclone was another reminder of the constant threat of extreme weather events that were becoming more frequent and severe due to climate change.
Launching a climate change film in Suva today he appealed to people to stay out of floodwaters.
He said Fiji was trying to adapt to "a frightening new era" and he urged people to support Fiji's global effort to tackle the root causes of climate change through its presidency of COP 23.