The Red Cross and the New Zealand and Australian governments are sending aid to areas of Fiji severely damaged by Cylcone Tomas.
UNICEF in the Pacific says at least 150,000 people could have been directly affected by the cyclone.
More than 17,000 people sought cover in 260 shelters during the weekend storm, which has now been downgraded to a category 3 cyclone as it heads out to open seas.
The Red Cross says people in Lau and Lomaiviti island groups have endured a horrific ordeal, and it plans to send aid with the help of Fiji's navy.
A naval ship is heading to the island of Cikobia, with about 400 residents, where it's thought aid is needed desperately.
Two Red Cross teams are also making their way by land to the northern and eastern parts of Vanua Levu to assess damage.
A spokesperson for Fiji's disaster management team, Laisania Tui, told Morning Report relief teams, including army and navy personnel, were leaving to assess the impact of the category 4 storm.
He says clearing debris, providing clean water, taking steps to avoid an outbreak of disease and clearing up 34 schools used as evacuation centres are priorities.
A state of natural disaster has been declared in Fiji's northern and eastern divisions.
UNICEF's deputy representative for the Pacific, Tim Sutton, says it could take a couple of days to assess the damage.
The storm stayed 200km to 300km southeast of Suva, sparing Fiji's capital, but there has been damage in Vanua Levu.
NZ, Australia send help
A New Zealand Air Force Hercules arrived in Suva, laden with relief supplies including tarpaulins, water containers and water purification tablets.
After landing in Suva, the plane is also expected to deliver supplies to Labasa in the northeast region of Fiji, where the cyclone was particularly fierce, and carry out reconaissance work.
The New Zealand Government has pledged $1 million, and is not ruling out giving more money if required.
Foreign Affairs Minister Murray McCully says New Zealand's offer of assistance has been accepted by authorities in Fiji.
He says an Air Force Hercules has already dropped one load of relief supplies in Fiji and has begun reconnissance work.
Australia will provide up to $A1 million ($NZ1.29m) in emergency humanitarian assistance.
An Australian Defence Force C130 was expected to depart as soon as weather permits and a commercial flight would also be available if required.
Wallis and Futuna damage
A damage assessment has revealed 80% of the crops on Futuna and half of the crops on Wallis have been destroyed.
Many homes have been damaged or flooded and half of the schools have been damaged when winds of up to 200km/h swept across the territory at the weekend.
The road on the northern side of Futuna has been washed away.
On Wallis, the main roads have been cleared and power has been restored along the south coast.
France is to release emergency funding, and a French air force plane has flown emergency supplies and disaster relief experts from New Caledonia to Wallis.