Disaster assessment teams in Tonga say water, shelter and food are the immediate needs for people still reeling from the destruction brought by Tropical Cyclone Gita overnight.
Local and international NGOs are working with the National Emergency Management Office (NEMO) to try and gauge the extent of the damage on the main island of Tongatapu, which hosts the capital Nuku'alofa and the nearby island of 'Eua.
Gita hit Tongatapu as a category four cyclone with winds of more than 233km/h. It has since moved away from Fiji and has been upgraded to a category five.
In Tonga, Gita ripped roofs off houses, brought down trees, destroyed a Catholic church, and took the Tongan Met Office and the national radio station off line.
Tonga police spokesperson Sia Adams said a 72-year-old man from Fuaamotu was rushed to the hospital last night, but died of a heart attack before arrival. She said the Director of Health said the cyclone could have contributed to his death.
Ms Adams also said police could confirm three major injuries and 30 minor injuries on Tongatapu as a result of Gita, and that police are still awaiting a report from 'Eua.
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Tonga's Red Cross said the level of damage to crops, homes, vegetation and infrastructure was extremely high following the cyclone.
Spokesperson Polikalepo Kefu said three teams from the Red Cross had been assessing different areas of Tonga and information was still being collated.
There had been a few people with injuries taken to hospital from 'Eua Island but he has not heard confirmation of any deaths, Ms Kefu said.
Many people were shocked and traumatised by the scale of last night's weather, he said.
"The scene in Nukualofa is very devastated... You can see fallen trees and even fallen houses, and they are still in a mess."
Mr Kefu said it was vital for people to begin repairs and try to clear up excess water to avoid an escalation of the dengue fever outbreak with the potential for mosquitos to breed in pooling rain water.
About 3000 people are at evacuation centres but Red Cross was expecting double that number overnight.
Meanwhile, former government minister in Tonga said almost all the crops on the island of 'Eua had been destroyed due the cyclone.
The category four storm went almost directly over 'Eua which lies just south east of the main island of Tongatapu.
Former 'Eua MP Sunia Fili said the storm had dealt a huge blow to the local agricultural sector.
"The kava, the cassava and yam too, all the crops near town. Also the breadfruit around in town and the town hall was down and also many small houses. Only the new houses was good but many families are in a very bad situation."
Sunia Fili said he had never experienced a storm of such intensity.
"I look at my neighbours, most of their houses are down, taking the walls or the upper parts of the house, and I am sure those people they are very sad at this time. They are looking forward for any aid from donors to help them but I can see they are still trying to get something to get in [to shelter]."
According to Sunia Fili, power is out across the entire island.
Local communities 'devastated'
Local youth worker Vanessa Helot said people in the communities she had visited were absolutely devastated by the damage and destruction to their homes.
"We are seeing shops that the rooftops have been uprooted; all their goods are exposed. We are seeing floods and also a lot of branches and a lot of electric lines. We have talked to some women this morning - their priorities are water, blankets and food."
She said it would have a huge impact on people's lives in Tonga.
"It is a big issue because this is their livelihood and it is like we have to start all over again. There is no electricity, there is no water. Not everyone has water tanks [or] has fresh water."
Nuku'alofa resident Joshua Saveeti described the scene as people in his neighbourhood emerged from their shelters, after what he said was a terrifying night.
" A neighbour just a few houses down, the roof went off, the walls are gone, and all that is left standing there is just all of their furniture and their things."
The family had evacuated earlier in the day, he said.
"They just got home this morning. We were all walking in and then they saw their house and then, yeah, they just lost it."
All airports in Tonga closed
All airports in Tonga are currently closed due to damage and disruption following Tropical Cyclone Gita.
The owner of Real Tonga Airways said there was no power at Fua'amotu International Airport on Tongatapu, where the airport buildings have sustained some damage and there is significant flooding.
Tevita Palu said he hoped the airport may reopen later tomorrow but there is major damage all around Tongatapu with trees down, roofs missing and a lot of debris.
New Zealand's Safe Travel website said international flights to Tonga and Fiji were likely to be disrupted and travellers are advised to check details with their airline and register with the Safe Travel website.
Emergency services struggling
Tonga's emergency services said they were struggling to get out and assess the damage after Gita left a trail of destruction.
Roads all over Tongatapu are blocked by debris and downed power lines hampering relief efforts.
NEMO staff said a full assessment of the damage may not be available until tomorrow morning.
There are unconfirmed reports two people have died.
Emergency services and His Majesty's Armed Forces headed out to assess the damage this morning.
NEMO spokesman Graham Kenna said the capital Nuku'alofa had been severely damaged.
"I've been involved in disaster responses for 30-plus years and it's the worst situation I have been in."
There had been major destruction, Mr Kenna said.
"A lot of the landmark buildings are extremely badly damaged or even destroyed, the landmark tree ... near the palace, has been been destroyed.
"It's quite a bad situation."
The armed forces rescued people throughout the night, including a woman who was in labour and a man who was very badly injured.
Mr Kenna said it was very difficult to get around Nuku'alofa.
He lives about 1.5km from his office but it took him 25 minutes to drive home due to downed power lines and debris on the roads.
The only positive aspects were that there was no storm surge because the worst of the cyclone hit at low tide, and that the cyclone did not last as long as was expected, Mr Kenna said.
The Tongan Advisory Council, an organisation originally set up to get emergency information to the Tongan community, said whole areas had been flattened by Cyclone Gita.
Chair Melino Maka told Morning Report people in the eastern districts will have borne the brunt of the cyclone and should be urgently targeted with aid.
"[We have] heard that homes, a school and churches have been flattened there.
"All the trees, all the greenery are down - and I think so far there was no loss of life and I'm happy about that - but as we go through the day we might start to see the full scale of the devastation," he said.
His nephew helped to rescue a man from a house that had collapsed.
Power and water supplies were out in Nuku'alofa and not even tank water was likely to be available because many tanks had been blown over, Mr Kenna said.
As soon as the worst of the wind was over, the armed forces began to clear the roads, Mr Kenna said.
"We wanted to make sure that once dawn breaks if we needed to get people to hospital we were able to do it."
A curfew would remain in place in Tonga for the rest of the day.
New Zealand and New Zealand govts to provide funds for cyclone relief
The New Zealand government has pledged $750,000 to assist rescue and relief operations in Tonga.
"So really it's just a matter of hearing from the Tongan government about what their needs are, and we will be ready to deploy," Prime Minister Jacinda Ardern told Morning Report.
The aim was to make sure there was no hold up from the New Zealand end, she said.
A RNZAF C130 Hercules aircraft carrying 12 tonnes of emergency relief supplies departed for Tonga today.
Defence Force Air Commodore Kevin McEvoy said the aid supplies included hygiene and shelter kits.
New Zealand is co-ordinating the international relief response alongside other countries including Australia.
Meanhwhile, the Australian Government is providing $US274,000 dollars worth of emergency aid as well.
Canberra said the aid had been given after a call from the Tonga Government.
The aid will be life-saving equipment including emergency shelter, kitchen and hygiene kits to assist over 2000 people in need.
Australia also released humanitarian supplies, including tarpaulins and water purification tablets, through the Tongan Red Cross.
The Australian Defence Force will also conduct humanitarian assistance and disaster relief operations, as part of the government's broader effort to support Tonga.
An RAAF C-17 will deliver the aid to Tonga tonight.
Mr Kenna said the New Zealand and Australian governments had emergency supplies on standby and emergency funds were available.
"We can hit the ground running. We're just dividing up our teams now so that as soon as we can get out there, we're out doing an assessment.
"We'll start in the city and then we'll fan out into the countryside and get a full grasp by mid afternoon on what the needs are going to be," Mr Kenna said.