New Zealand's Foreign Minister Murray McCully says the government in Vanuatu is overwhelmed by the scale of the disaster left by Cyclone Pam.
He has announced an additional US$1.1 million in relief, bringing to US$1.8 million New Zealand's contribution so far.
Mr McCully said the cyclone had left behind a substantial humanitarian challenge which will test the region.
"I've only had the report from the [NZ] High Commissioner and it's fair to say that the government there is pretty much overwhelmed by the scale of the task that they now confront, and they can't even begin to scope out the immediate task because of the lack of reporting from the outer islands."
Mr McCully said New Zealand was looking at what could be done to restore communication to outer areas.
He also said New Zealand was looking at getting medical supplies to Tuvalu, which suffered storm surges from the cyclone.
But he said Fiji and the Solomon Islands, which were also affected, appeared able to cope without international help.
Listen to the full interview with Murray McCully on Dateline Pacific
Mr McCully said, once the extent of the destruction was known, it was likely New Zealand would offer significantly more aid.
The initial contribution would go towards providing temporary shelter, medical kits, basic food supplies and water.
Prime Minister John Key said New Zealand's thoughts were with its Pacific neighbours.
"Clearly it remains a very difficult situation in the affected countries and we will continue to do all we can to help our Pacific neighbours," he said.
"The Ministry of Foreign Affairs and Trade (MFAT) consular offices are contacting New Zealanders in Vanuatu to confirm their wellbeing. At this stage, the ministry has not received reports of any New Zealand casualties."
Mr Key said there would be space on military planes returning from Vanuatu for New Zealanders who urgently needed to return before commercial flights resumed.
He said priority would be given to those with medical conditions, the elderly and families with young children.
New Zealand aid to Vanuatu underway
On Sunday, a New Zealand military plane transported eight tonnes of supplies and an initial team to assess and assist on the ground.
The New Zealand Defence Force has flown two more relief missions into Vanuatu today taking supplies, relief workers and medical personnel to help with the recovery.
The first Air Force Hercules flight left Whenuapai at around 10.00am and the second at around 1.30pm.
Images from agencies, social media
Radio New Zealand correspondent Len Garae, in Port Vila, said planes from New Caledonia, Australia and New Zealand had already arrived.
Mr Garae said the international response had been rapid.
"The assistance that's coming up seems to be faster than during the previous years and it is also possible that's because of the early appeal that has been put out by the head of state while attending a disaster relief meeting in Japan.
"He delivered a highly emotional appeal to the international community so assistance is coming in faster than in the past."
The consignment from New Zealand included first aid kits, tarpaulins for emergency shelter, water containers, chainsaw packs and generators.
Specialist personnel from New Zealand Government agencies and the New Zealand Red Cross have also been sent, to assist in providing advice to the High Commission and to help carry out a needs assessment which would shape further assistance.
RNZI / Koroi Hawkins
Red Cross relief to focus on immediate needs
Red Cross New Zealand's Communications Manager Hanna Butler was on the first New Zealand Defence Force (NZDF) Hercules flight out today.
She said that, following yesterday's first military relief flight, the Red Cross had a request from its Vanuatu office to send over more relief in the form of water containers, tarpaulins and first aid kits.
Ms Butler said the situation on the ground was grim.
"I think like everyone we're still trying to understand the full extent of the damage," she said, "but we do know that the impact Cyclone Pam's had on Vanuatu is enormous, and the humanitarian need there is just going to be huge."
Information about the post-cyclone situation on Vanuatu's outer islands was starting to filter in.
Ms Butler confirmed the Vanuatu Red Cross had managed to communicate with Torres Islands and Tanna
"From what I understand the Torres Islands is okay but there is a lot of devastation on Tanna," she said.
"I have heard through my colleagues that the island is simply flattened. Schools and concrete homes, even the concrete homes across Tanna have been destroyed."
Red Cross Emergency Communications Officer in the North Island Graeme Langford said 1800 ten-litre water containers, 250 shelter kits and 2400 tarpaulins were initially being sent.
He said aid workers and a communications specialist would also be sent, and more personnel and supplies were ready to go if needed.
Royal New Zealand Air Force operations head Air Commodore Kevin McEvoy said the Air Force was well trained and equipped for such missions.
"Pacific nations such as Vanuatu are our friends and neighbours and we're happy we can help at times of need," he said.
"The C-130 Hercules is an ideal platform for operating into areas that may not be accessible to commercial aircraft. With the main airport being closed to civilian transport, a Hercules load makes a real difference in situations like this."
NZ to help with long-term recovery
Mr Key said the Government would be doing more to help Vanuatu, including longer term redevelopment.
The first priority had been to check on the safety of people there, including New Zealanders and the second to restore basic services, and, eventually, to look towards long term development.
"These islands are subject to cyclones from time to time so using this process to strengthen the infrastructure is important," Mr Key told Morning Report.
Listen to John Key