Authorities are now considering imposing a state of emergency in the western division of Viti Levu after the flooding forced thousands of people to flee their homes.
The body of a 20-year-old Fijian man was found in a creek, and another Fijian man, in his 40s, was found dead after becoming trapped in a car in floodwaters.
In addition, a woman died at an evacuation centre last night, possibly due to complications as she had diabetes.
Heavy rain, which has been falling since Thursday, has cut power and washed out roads and bridges, leaving residents stranded.
The towns of Sigatoka, Nadi, Lautoka, Ba and Rakiraki are cut off.
The government is asking airlines not to fly into the country this weekend.
All Air Pacific flights to Nadi for Saturday and Sunday have been cancelled, however the airline's outbound flights will continue to get all passengers to their overseas destinations.
An Air New Zealand flight from Auckland to Nadi on Saturday had to return to Auckland, effecting hundreds of passengers.
Fiji's Disaster Management Office says more than 3000 people spent the night in evacuation centres. It fears the worst for some people who have been reported missing.
The Office says the floods could be the most extensive ever recorded.
Its director, Pajiliai Dobui, says the rain was more intense than in the big floods of 2009 and many people were caught out because the flood waters rose so quickly.
It's the second flooding this year in Fiji. Flooding in January claimed the lives of five people in Ba district.
The Prime Minister of Fiji, Frank Bainimarama, has been assessing damage caused by the flooding.
Mr Bainimarama has told officials "to think outside the box" to ensure the safety of Fijians during the disaster.
Call for help
The Office says it needs more boats to assist those trapped in the flooding. It has been told by a number of callers that they have witnessed people being washed away in the flood waters.
Several Air Pacific flights to and from Fiji have been cancelled or delayed. Nadi International Airport was closed on Friday night and all domestic and international flights cancelled.
The New Zealand Ministry of Foreign Affairs is advising people travelling to Fiji to check with their airline.
Acting chief fire officer Qio Moceitai says his staff have, so far, assisted more than 100 people.
He says they need more equipment to help with rescues and have not been able to check if people are safe in the villages which are cut off.