UPDATED: 5.47PM Fijian authorities are urging people to avoid unnecessary travel, with two tropical depressions expected to make landfall this afternoon.

The Nadi Weather Office said the depressions will bring strong winds and heavy rainfall to the Central, Western and Northern Divisions from this afternoon until Thursday morning.

LISTEN ABOVE: Greenpeace Pacific's Matisse Walkden-Brown talks to Larry Williams from Nadi

Fijians are being urged to take safety precautions, with fears one of the depressions will develop into a cyclone in the next 24 to 48 hours.

Permanent Secretary for National Disaster Management Meleti Bainimarama said families living in flood-prone areas need to move the nearest evacuation centre immediately.

He said farmers will need to move their livestock to higher ground and secure their property, and families should make sure they have essential supplies.

Greenpeace head of Pacific Matisse Walkden-Brown is in Nadi and told Larry Williams almost 600 millimetres has fallen in 48 hours.

She said towns are shut, Sigatoka Bridge is underwater and hundreds of people are in evacuation centres.

Walkden-Brown said the two depressions could merge to form a tropical cyclone.

"There's a 60 per cent chance it's going to change into another cyclone over night, not as big as Cyclone Winston, but still going to contribute to some heavy flooding".

The body of a 70-year-old man who went missing last night has been recovered from the Sabeto River in Nadi.

Police are still searching for a 19-year-old woman who went missing while attempting to cross the same river yesterday afternoon.

The Nadi Weather Office says two depressions are likely to bring more severe weather to the country tonight.