THE whole of the Fiji Group has been put on a heavy rain alert until Friday by the Nadi weather office.
And members of the public have been warned that heavy rainfall could also cause flash flooding.
Senior meteorologist Amit Singh said the heavy rain alert was a result of an active trough of low pressure with cloud and rain slow moving over Fiji.
"We will experience heavy rain at times with squally thunderstorms," Mr Singh said.
He said the weather conditions was expected to clear-up by Friday afternoon.
Mr Singh said with the current weather condition experienced in the country, seas would be moderate to rough.
He advised mariners to take necessary precautions and take heed of weather warnings.
He said members of the public should also refrain from going near flooded rivers and creeks.
Meanwhile, torrential rainfall on Tuesday night resulted in flash flooding in low lying areas in the greater Nausori area.
The Waidamu River in Vuci South Rd, Nausori burst its banks early yesterday morning.
Some areas along the Waila Feeder Rd, Korociriciri Rd and Vusuya Rd in Nausori were also under water yesterday.
Nausori resident Arti Devi said they had put up shutters and sealed windows because of the heavy rain.
Ms Devi said they had taken their animals to higher ground and placed their belongings in a safe place.