Tongan authorities are on standby as tropical cyclone Sarai heads towards the outer islands.
Two people have died during Sarai in Fiji, where the body of a man was found after he went missing in a river during the storm, and another drowned while swimming.
A third person has been hospitalised after being hit by a falling tree.
The Fijian Broadcasting Corporation reports the body of a man, in his late 40s, was recovered in Naivucini, north of Suva inland on the main island Viti Levu.
Cyclone Sarai continues to bring storm force winds and rain to much of Fiji.
At it's centre, Sarai's winds are reaching up to 120 kilometres per hour, with some gusts to 170 kilometres per hour.
The cyclone is predicted to make landfall over Tonga's Vava'u island group on Monday or Tuesday, as a category one storm.
The cyclone has been affecting Fiji for the past 36 hours, bringing widespread flooding and some damage.
Disaster officials in Fiji say their focus is now on ensuring the people of the Southern Lau group are prepared for the slow moving storm.
Cyclone Sarai track from the Fiji Met Service. Photo / Fiji Met Service
The National Emergency Operations Centre said 70 evacuation centres around Fiji are in use with 2538 people sheltering there.
It said it is working with the Ministry of Health on initial assessments for affected areas before the green light will be given for families to return home.
It could take upto a week to restore full power to Fiji's main island, Viti Levu.
Many people across parts of the Central, Western and Northern Divisions have been without power supply since Friday night.
Energy Fiji Limited (EFL) said in order to energise the entire EFL network in Viti Levu, they need to inspect the over 10,500 kilometres of power network and over 102,000 concrete and wooden poles which includes steel towers in Viti Levu.
The CEO of Energy Fiji Limited Hasmukh Patel has already said full restoration to all areas in Viti Levu could take up to one week.
Fiji Village reports Energy Fiji Limited said teams started inspections on Friday but it is was slowed down by the wind and rain.
The priority areas at the moment are hospitals and health centres as well as water treatment plants.
Hasmukh Patel said strong winds caused damages to the electricity infrastructure, especially on the overhead lines cross arms and other associated accessories.
He adds that power supply in Viti Levu was affected and this meant that every metre of the power line has to be physically inspected, repaired where required, before it can be energised.
He said while this process was time-consuming, it was none-the-less critical to ensure the safety and security of power supply.
Meanwhile, the Tonga Met Service is forecasting that winds will lift from this evening as the cyclone moves toward Tonga's Ha'apai and Vava'u group.
The storm's major impact on Tonga is forecast to occur from New Year's Eve.
A Red Cross Disaster Management Coordinator, Anaseini Iotebatu, said evacuation centres in Tonga were already being set up with emergency supplies.
"We have groups of volunteers in the community where they have been on standby as well," she said.
"Our relief supplies was replenished in November ... relief supplies in Tongatapu are also on standby."
Iotebatu said the Red Cross was attending regular briefings alongside other agencies including police, and the Fire and National Emergency Management Office.
