Cyclone Evan has left a trail of devastation in Samoa and Fiji and is heading towards New Zealand.
New Zealand's MetService says the cyclone is tracking south away from Fiji, with flights to and from the country are expected to resume later on Tuesday.
Thousands of people took refuge in evacuation centres on Monday night, as the cyclone pounded northern parts of Fiji causing flooding and extensive damage.
Strong wind and heavy swell warnings remain in place, but flights to and from Fiji are expected to resume later on Tuesday.
Thousands of people took refuge in evacuation centres overnight, while roads were closed and power and water supplies were cut to northern parts of Fiji.
Police were restricting the movement of people in and out of main towns and cities to ensure public safety, the Fiji Times reported.
Fiji's second-biggest city Lautoka, near the international airport at Nadi, was severely battered by the cyclone, with resident Janet Mason telling Radio New Zealand that an empty house had "flown through the air" and landed beside hers.
The cyclone earlier battered Samoa, leaving four dead, and a New Zealand Air Force Orion is continuing to search for 10 fishermen from four boats who are still missing.
Damage to the main island of Upolu appears to be worse than from the 2009 earthquake and tsunami that killed 135 people.
Cyclone Evan is expected to pass within kilometres of NZ's northern North Island over the weekend, by which time it is unlikely to be a tropical cyclone - "but this is by no means certain", MetService chief forecaster Peter Kreft said.
"We're very conscious of the possibility of a track which takes Evan near East Cape. This would be a totally different ball game."
New Zealand Prime Minister John Key said the government had received a request for assistance from Fiji.
"We're working through an assessment of the damage and where we might best be able to help," he told New Zealand television.
"I suspect part of it will just be sending money. There's reasonably widespread damage in both Samoa and Fiji, so they'll need to restore a lot of their core infrastructure."
A large amount of tropical air from the cyclone means potentially heavy rainfall in places, including Northland, Auckland and Coromandel over the weekend, and strong onshore winds.