The Fiji Meteorological Service says by the time a tropical depression near the country turns into a cyclone it is likely to have moved to open waters or closer to Tonga.
A senior forecaster, Terry Atalifo, says the depression is currently located north of Labasa on Vanua Levu, and is slowly moving east-northeast.
He says it is still possible the depression will not develop into a cyclone, but if it does, it will not be until Sunday or early next week.
"It will depend on how far it moves eastwards, because if it moves further east then it might affect the southern parts of Tonga. But if it continues to track more of a south, south-east direction, then it will not affect any of these small islands in the Fiji group, nor in the Tonga group."
Flood alerts and road closures have now been lifted.
Tongan forecasters have issued a strong wind warning and have advised people to be prepared for extremely high tides, damaging swells and heavy rain.