Volunteer Service Abroad said it could still not account for four Kiwi volunteers in Vanuatu.
Read more: Cyclone Pam live updates
Speaking to TV3's Firstline this morning, VSA spokesman Junior Ulu said the agency ensured that prior to Cyclone Pam hitting, its volunteers were in secure accommodation.
"We have our processes and procedures in place to make sure they're safe, and solid structures, extra food, and we were in communications with them right up until the time the cyclone hit.
"We have been able to contact volunteers in Port Vila, and also in Luganville and Santo - but because communications are down it's been harder to connect with the volunteers who are in the outer islands."
Mr Ulu said they had worked with the Ministry of Foreign Affairs and Trade and other non-government organisations that were moving into the space, to find out how they can help "connect" and "communicate".
"Last communications we had with them was that they were bunkering down and making sure they were safe."
Prime Minister John Key told Newstalk ZB as it was "very early days", it was difficult to know what damage had been caused by Cyclone Pam.
"I spoke to the Prime Minister of Vanuatu last night. He is going to give us the best assessment he can as he can get more information available."
Mr Key said a Hercules was sent with supplies yesterday, and two more would be sent today.
Herald journalist Kirsty Johnston is at Whenuapai Airbase. On board the plane were emergency management crew, health officials, a member of the MFAT and logistics staff.
A Hercules aircraft with NZ media and Government officials on board is due to fly out at midday.
Auckland, Northland through the worst
Auckland and Northland are through the worst of Cyclone Pam, with 2000 people out of power overnight and trees toppled in Northland, while the category three cyclone surges towards Gisborne.
Auckland Civil Defence controller Clive Manley says most of the power outages have been fixed and "only a handful" of households remained without electricity.
He said the impact was "not as severe" as previously thought, with waves half the expected height and less rainfall.
Mr Manley said Pam was "still a powerful cyclone" however, and is expected to hit Gisborne hard this afternoon.
A spokeswoman from Auckland Airport said some flights had been delayed and rescheduled this morning, including an Air New Zealand flight to Vanuatu's capital, Port Vila.
All ferry services were cancelled from Gulf Harbour this morning, as well as a 6.15am sailing from Half Moon Bay.
Northland appears to have had a lucky escape from Cyclone Pam with only a few fallen trees and power outages reported.
Tony Phipps, group controller for the Northland Civil Defence Emergency Management Group, said this morning there were no reports of serious damage or injury linked to the cyclone.
Mr Phipps said Northland Regional Council figures showed the highest rainfall between yesterday afternoon and early this morning had been 67.5mm at Glenbervie, while the maximum wind gust recorded at Cape Reinga yesterday had been 118.5kmh.
"Emergency services have reported a quiet night with few storm-related incidents, although daylight may reveal some damage that we are as yet unaware of, given the heavy seas off Northland's east coast overnight."
Fire service area commander for Whangarei and Kaipara Mike Lister said five minor calls were received last night, mainly to report trees down on roads.
A taskforce of firefighters arrived from Auckland last night to keep tabs on Cyclone Pam, however Mr Lister said he believed they did not attend any incidents.
"Our team of volunteers would have gone to the calls so the Auckland crew were on standby. We were very, very lucky," he said.
About 50 customers in the Waiotemarama Gorge area in South Hokianga have been without power since about 11pm last night. Top Energy spokesman Peter Heath said most faults were caused by trees in or across lines and said the outage was expected to end at 1pm today.
Mr Phipps said given the devastation Cyclone Pam had caused in the Pacific, Northland - which often bears the initial brunt of tropical cyclones that reach New Zealand - had been fortunate it had eased as predicted as it drew closer.
"Our thoughts are now with those in the Gisborne, Hawkes Bay and Bay of Plenty areas which are expected to feel Pam's effect a bit more severely."
Last night the cyclone was expected to weaken to a category 3 storm - down from the category 5 brute which smashed Vanuatu - by midnight overnight, when it was forecast to be centred 420km north of East Cape.
But it is still expected to "wallop" the East Cape, Eastern Bay of Plenty, Gisborne and northern Hawkes Bay with potentially destructive winds today.
Homes were evacuated in some areas yesterday, and the Defence Force, Fire Service, ambulance, police and roading and power companies drafted in extra staff.
By midday today, the cyclone was expected to lie 240km east of East Cape, and would lie 470km east of Napier by midnight tonight.
Severe weather warnings are in place for northern and eastern parts of the North Island, as heavy rain and gales were forecast until tomorrow.
Heavy rain, severe gales and large swells were hitting the upper North Island last night, with Civil Defence and forecasters warning people to prepare for the full brunt of the storm.
Eastern areas from Northland down to Hawkes Bay were expected to be worst hit.
Civil Defence Minister Nikki Kaye warned communities in those areas to "make sure you have good preparations in place".
In Hawkes Bay and Gisborne, Civil Defence managers advised residents to prepare for periods without electricity.
"People need to make sure their family emergency plans are up to date, with their properties prepared for strong winds, and a getaway kit all ready - just in case," Hawkes Bay Civil Defence group manager Ian Macdonald said.
In Gisborne, emergency manager Richard Steele warned people against travelling, as gusts of up to 150km/h and 9m swells were forecast. Flooding was possible with up to 200mm of rain expected.
"Swells are expected to inundate State Highway 35, to the north of Gisborne, in several places adjacent to the coast," he said. Tolaga Bay and Tokomaru Bay could bear the brunt of the storm, he said.
"Police, the army, fire, St John, health, roading and network services have moved extra people and equipment into various townships on the East Coast to help keep people safe.
"Virtually all people have been moved from Anaura Bay and Nuhiti, where the road has been closed as a precaution."
Destruction in Vanuatu
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Historical information: Cyclone Bola
Twenty-seven years ago almost to the day, New Zealanders were picking up the pieces from one of the most damaging - and costly - cyclones in its history.
Cyclone Bola brought devastation when it hit in March 1988, including severe slips, erosion, an estimated $90 million in horticulture and farming losses, the forced evacuation of thousands and the death of three people whose car was swept away by floodwaters.
Bola formed on February 24, 1988 near Fiji, and reached hurricane winds near Vanuatu four days later. It affected about 3000 houses and 15,000 residents.
Bola's southeasterly path was blocked by an anti-cyclone north of New Zealand, holding it in a roughly stationary position while it caused widespread damage to the country.
Bola hit Hawkes Bay and the Gisborne-East Cape region of the North Island on March 7, creating some of the heaviest rainfalls for a single storm in New Zealand's history.
A peak rainfall of 916mm over the three days was recorded inland from Tolaga Bay. Other locations received more than half of their annual rainfall totals from the storm.
Winds of up to 100km an hour toppled trees and tore off roofs, while the torrential rain caused landslides, cut power and sewage services, and closed several roads.
States of emergency were declared in Wairoa, Gisborne and the East Cape.
Te Karaka township, inland from Gisborne, was almost flooded by the Waipaoa River and it was feared Wairoa, in Hawkes Bay, would be inundated with overflow from nearby river banks.
Emergency and civil defence services evacuated 3000 people from Gisborne, 400 from Te Karaka, 300 from Wairoa. Horses had to be used to get some people not accessible by helicopter.
Northland was also affected by Bola. The region's main water supply was disrupted when the line carrying the water was washed away with a bridge, power and telephone lines were cut and a state of emergency was declared in Dargaville.
Almost 1800 farmers and about 3600 hectares of farming and horticultural land were affected.
The cost to the Government was more than $111 million.
NZ Herald: Teuila Fuatai, Kirsty Johnston, Isaac Davison, Nicholas Jones
NZME.: Patrice Dougan and Nikki Papatsoumas.