The Pacific island nation of Vanuatu has lost years of development progress and must "start over" after a powerful cyclone ravaged most of the islands' buildings, the country's president said.

Baldwin Lonsdale in an interview on Monday said that Cyclone Pam destroyed or damaged 90 percent of the buildings on the main island of Port Vila.

Lonsdale, visibly weary and red eyed from lack of sleep, said that he and other top government officials were preparing to return home from Japan, where they were attending a disaster conference before the cyclone hit the country.

"This is a very devastating cyclone in Vanuatu. I term it as a monster, a monster. It's a setback for the government and for the people of Vanuatu," the president said.

He said information from other islands was not available because most communication links were still not working. But the airport in Port Vila has reopened, allowing aid and relief flights to reach the country.

"There is a breakdown of communications, we cannot reach our families and we do not know whether our families are safe or not," Lonsdale said.

He also said that climate change is "contributing to the disaster."

Australia, which along with New Zealand and France is providing rescue and relief help, offered transport from Sydney to Port Vila, his staff said.

Lonsdale said that the limited information he was able to get from home showed eight people confirmed dead on Port Vila after the 300kph winds smashed across the Vanuatu archipelago.

Logistical challenge

Al Jazeera's Andrew Thomas, who is reporting from Port Vila, described the capital as "badly damaged but not quite devastated" with majority of the buildings sustaining some damage or totally destroyed.

"The real concern though is the outlying islands," our correspondent said.

"Aid agencies have not been able to land there. So far, they have done reconnaissance flights, and anecdotally what I have been told, from the air, it does look like total destruction on those islands."

The number of human casualties also remains unknown, he said.

In an interview with Al Jazeera, Kyung-Wha Kang, a UN Assistant Secretary-General for the UN humanitarian office, told Al Jazeera that determining the extent of the damage "is extremely difficult" because communication have been totally cut off especially in some of the islands.

Relief flights have begun arriving in the capital, but workers on the ground said there was no way to distribute desperately needed supplies across the archipelago's 80 islands.

Save the Children's Vanuatu director Tom Skirrow told AFP news agency the logistical challenges were even worse than Super Typhoon Haiyan, which struck the Philippines in November 2013, killing more than 7,350 people and ravaging an area a big as Portugal.

Skirrow said 15,000 people were homeless in Port Vila alone and flights over remote islands had confirmed widespread destruction elsewhere in the impoverished nation of 270,000.

Source: Al Jazeera and agencies