A Damaging Heavy Swell Alert is now in force for the open waters of Southwest Viti Levu and Lau, the Koro Sea and the Kadavu Passage.
The Nadi Weather Office says a high-pressure system located to the southeast of Fiji is expected to generate and direct damaging large ocean waves.
They say damaging heavy swells with heights of up to 4.5 metres and wave periods of up to 18 seconds are expected to develop from Thursday.
The Weather Office says mariners, fishermen and operators of small vessels are being urged to exercise extreme caution.
People living in coastal areas are also advised to remain alert as sea conditions are expected to become hazardous.
Stay with us for updates.