Disaster management officials in Tonga say they have serious concerns for residents on more than twenty low-lying islands battered by Cyclone Ian.
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 up to 270 kilometres per hour swept through Tonga's northern and central areas over the weekend.
There's been extensive damage to the islands and at least one person was killed.
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.
Relief efforts are underway with the United Nations working with the Red Cross to inspect the hardest hit areas.
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.
"The trees are uprooted and there's electric poles that are broken and lines on the roads."
Tonga's director of emergencies, Leveni Aho, told the ABC there is still no communication with 80 per cent of the worst-hit Ha'apai island group, including Lifuka which bore the brunt of the storm.
"The picture comes to hand now, it was really bad," he said.
"We have got some people sheltered in some of the evacuation centres, buildings and some of the churches."
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.
No contact yet
Until authorities have reached smaller out-lying islands, where no contact has yet been made, it will be unclear what the full extent of damage or injuries is.
The United Nations says it is working with Tongan disaster officials to help coordinate the relief effort for islands affected by the cyclone.
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.
UN OCHA says an information management and mapping specialist is expected to arrive in the Ha'apai Islands on Monday, after which a team will meet to plan any further response.
Joint effort pitching in
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.
The country's main telecommunications provider, Digicel, sent a team with equipment to start restore communications.
Technicians are working to fix internet and mobile phone services.
The group also took emergency supplies from the Red Cross and church groups.
Cyclone Ian was packing winds 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
18:43 EDT Severe thunderstorms and damaging winds have caused chaos across Sydney, with the SES looking at more than 250 jobs, mainly roof damage from heavy rain and strong winds.