Cyclone Evan battered the South Pacific island state of Fiji with 200km/h winds on Monday, cutting power and water supplies in the northern region.
Thousands of people took refuge in evacuation centres and airlines suspended flights in and out of the country.
The military government warned that Evan could be the most destructive cyclone since 1993 to hit the island, one of the Pacific's biggest tourist centres.
Fiji government spokeswoman Sharon Smith-Johns says the cyclone was moving towards Nadi and had intensified a little, with winds of up to 200km/h.
Ms Smith-Johns said 3500 people are sheltering in evacuation centres after people had earlier been warned to prepare for the worst.
She said the lack of early casualties was encouraging but people could not become complacent.
"We've had a week to prepare for this, so we're as prepared as you can be," she told Radio New Zealand on Monday.
"The extent of the damage I don't think we're going to know until tomorrow morning when we wake up and see how badly it has hit."
Fiji's second-biggest city Lautoka, near the closed international airport at Nadi, was severely battered by the cyclone, with resident Janet Mason telling RNZ that an empty house had "flown through the air" and landed beside hers.
The bulk carrier ship Starford, believed to be carrying equipment for a Chinese firm constructing a highway, dragged its anchor and was pushed onto the reef in Suva Harbour, the Fiji Times reported.
Meanwhile, New Zealand searchers looking for 10 fishermen missing off Samoa since the cyclone hit the island nation believe they have found one of four missing boats.
The upturned fishing boat hull is being towed to Apia by Samoan Police launch after being found by a New Zealand Air Force Orion searching for the fishermen.
Four people have already died and more casualties were feared, as damage to the Samoan island of Upolu appeared to be worse than from a 2009 earthquake and tsunami that killed 135 people, according to aerial surveillance, a spokeswoman for the prime minister told RNZ.
New Zealand Red Cross has deployed a specialist team and an emergency grant of $NZ10,000 to help deal with the damage.
Air NZ is allowing all passengers flying from Auckland to Apia between December 17 and December 30 to take one extra piece of checked luggage, up to 23kg, free of charge.