Authorities in Fiji are struggling to make contact with remote islands days after the country was slammed by a destructive cyclone, amid fears the many displaced people could next be overwhelmed by widespread disease.

Aid has begun arriving in Fiji where more than 8000 people have taken refuge in evacuation centres following the havoc wreaked by Tropical Cyclone Winston, which struck late on Saturday, bringing lashing rains and winds of up to 330km/h.

For some, it could be months before they can return home and many remain cut off from the world.

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While the official death toll on Tuesday had risen to 29, it’s expected that figure will grow as communications are restored and help begins to reach outlying islands.

An aerial shot of the destruction from Cyclone Winston in Tavua, Northern Fiji. Photo: Fijian Government

The death toll includes eight bodies found on the island of Koro, which took a direct hit from the cyclone as it passed over the western side of the country.

“It has pretty much flattened,” Fiji government spokesman Ewan Perrin told Radio New Zealand on Tuesday.

“There are very few buildings left.”

Aid groups and government authorities are also racing to deal with a critical need for clean water, health supplies and emergency accommodation after power lines, roads, jetties and homes were destroyed and damaged across huge areas of Fiji’s main islands of Vanua Levu and Viti Levu.

The roof of a primary school in Fiji is torn away as a result of Cyclone Winston. Photo: ABC

The lack of shelter and clean water has raised fears of an outbreak of disease.

“It really is a race against time to get immediate relief to those who have lost everything and ensure families can stay safe and healthy,” CARE Australia spokeswoman Sarah Boxall said.

A 30-day state of emergency has been declared and Prime Minister Frank Bainimarama has ordered emergency officials to respond to the crisis as quickly as possible.

“There are Fijians out there who are without water, without a roof over their heads, without food and without essential services,” Mr Bainimarama said.

An Australian Defence Force C-17 Globemaster aircraft carrying urgent humanitarian supplies has arrived in Fiji, while four helicopters which will help carry out disaster assessments are also being sent.

A P-3 Orion surveillance aircraft was on standby.

The Australian government has said it could provide more assistance if needed.

-AAP