Tongan authorities say they have made contact with most of the smaller islands battered by Cyclone Ian with reports of extensive damage and at least one person killed.
Contact with small northern islands of the Ha'apai group, home to about 8,000 people, was lost when the category five storm packing winds of more than 200 kilometres per hour swept through the area over the weekend.
Communication and power is still limited in some areas and there is concern for the well-being of residents on low-lying islands.
Tonga's Prime Minister Siale'ataongo Tu'ivakano has returned from inspecting the damage to Ha'apai, as well as visiting those affected.
Lord Tu'ivakano went with the Australian and New Zealand High Commissioners, a group of nobles and the speaker of Parliament, Lord Fakafanua.
A state of emergency remains in place for the Ha'apai and Vava'u groups of islands, which were hardest hit by the cyclone.
The director of Tonga's Disaster Management Team, Leveni Aho, says it appears some smaller islands were lucky to escape serious damage.
"The path of the cyclone was very narrow indeed, so it hit some islands, and yet the neighbourhood about 40 to 50 kilometres away was almost untouched," he said.
Mr Aho, who is co-ordinating the emergency response to the disaster, says he's surprised there are not more casualties.
"We haven't had any further reports of any deaths, which is very good indeed, and looking at the amount of devastation it was a miracle that not more than one person has a loss of life."
He says residents on some of the low-lying islands are being moved to higher ground after a sea surge left flooded some of their homes.
The Governor of Ha'apai, Tu'i Ha'angana, has visited the area and says the damage is so bad he can see from one side of the island to the other.
Journalist Monalisa Palu is on the ground in Ha'apai, and told Radio Australia's the main town of Pangai on Lifuka island is without power and people are desperate for assistance.
"It's just devastating seeing homes that were here last month destroyed, families sitting outside trying to ravage through whatever remains there are," she said.
"I'm actually right now looking at some kids playing by a big uprooted tree, and there's a boat by the side of the road showing how much surge there was.
"The residents here described howling winds, one of the town officers told me he has lived through a couple of cyclones and this is probably the worst he has ever seen."
Relief efforts are underway with the United Nations working with Tongan disaster officials and the Red Cross to inspect the hardest hit areas.
The secretary general of Tonga Red Cross, Sione Taumoefolau, says tents and other supplies will be given to residents who have lost everything.
"There's a lot of houses that are down, about 80 per cent of the buildings have gone, so the people have been staying in evacuation centres," he said.
There is also significant damage to infrastructure and vegetation.
Sune Gudnitz from the UN Office for the Coordination of Humanitarian Affairs based in Suva says once more details become available about the true extent of the damage the United Nations will be able to provide more assistance.
"Logistically in the Pacific, by nature as you are aware it is always a challenge to get around," he said.
"But I think we are fortunate in this sense that the airport, the main airstrip in Ha'apai has only minimal damage, so it is possible to land in a plane which is always a good start.
"The moment we have any clarity on the need from the ground, we can mobilise through the Pacific Humanitarian team, sectorial expertise to go in and support the government in providing shelter, working with partners on the ground."
Two Tongan navy patrol boats have gone to the northern and southern Ha'apai islands to survey immediate damage, with one boat delivering emergency shelter supplies and road clearing equipment.
A chartered flight flew health, power, telecommunication and Red Cross personnel to Ha'apai on Sunday afternoon.
New Zealand has pledged $NZ50,000, or $US42,000, for immediate response efforts and sent in the air force to assist in assessing damage.
The New Zealand Air Force Orion is too large to land on the airstrip in Ha'apai, but has conducted an initial aerial surveillance of the affected areas providing important information for the relief effort.
UN OCHA says other non-government organisations such as Caritas and Oxfam are preparing to send response support staff.
Technicians are working to fix internet and mobile phone services.
However, Tongan New Zealanders are frustrated that Tonga has not officially asked New Zealand for assistance with the clean-up from Cyclone Ian.
The head of the Tongan Advisory Council in New Zealand says many Tongan churches and community groups in New Zealand want to contribute to relief supplies.
Melino Maka says without a formal approach by the Tongan Government to their New Zealand counterparts, it will be difficult to get containers with goods to the affected island quickly.
"It's quite frustrating for the community who constantly want us to make things happen, but we do not have any other way or other means at the moment," he said.
Cyclone Ian was packing winds with gusts of close to 300 kilometres per hour as it smashed into the northern Tongan islands early Saturday local time.
It briefly weakened to a category four system before building up again to category five as it tracked south-southeast, bringing gale winds to the capital, Nuku'alofa.
However Tongan authorities say Nuku'alofa, on the main Tongatapu islands in the south, as well as the central Vava'u island group, did not sustain as much damage as expected.
© ABC 2014
16:04 EDT The swirls, twists, and curtains of light of the aurora australis were visible from the Australian and New Zealand mainland overnight.