The United Nations Children's Fund in Fiji says several thousand people may have been left homeless by Cyclone Mick.
Two people are confirmed to have died after the category two storm swept over the main island of Viti Levu, after passing over the tourist destinations of the Yasawa and Mamanuca islands yesterday.
Fiji's National Disaster Management Office says a young boy was killed by a falling tree and a 23-year-old man drowned during the storm.
Two other people are still missing, after being swept away by currents.
UNICEF's Pacific Deputy Representative Tim Sutton says early indications are that at least 2,000 people have been displaced by the cyclone.
He says the flooding will particularly effect the very vulnerable, such as families living in informal settlements that are near to rivers and low-lying areas.
Mr Sutton says UNICEF staff are today assessing the most urgent needs and providing basic supplies such as collapsible 10-litre water containers and water purification tablets.
He says they also have medical supplies in stock in Suva and will be distributing these today.