SYDNEY - The first humanitarian flights arrived in volcano and tsunami-stricken Tonga Thursday, five days after the dual disaster cut the Pacific nation off from the rest of the world.

Tonga has been inaccessible since Saturday, when one of the largest volcanic explosions in decades cloaked the kingdom in a layer of ash, triggered a Pacific-wide tsunami and severed vital undersea communication cables.

Officials said military transport planes from Australia and New Zealand touched down at Tonga's main airport -- only recently cleared of a thick layer of ash after painstaking effort.

A "C-17 Globemaster left from Amberley Airport Base around 7:00 am today (2000 GMT)," an Australian defence official told AFP.

"The aircraft is carrying humanitarian aid and disaster relief supplies, including water containers, kits for temporary shelters, generators, hygiene and family kits, and communications equipment," New Zealand foreign minister Nanaia Mahuta said.

The first smattering of images to emerge from Tonga's capital Nuku'alofa show ashen buildings, toppled walls and streets littered with boulders, tree trunks and other debris.

More than 80 percent of the archipelago's population of 100,000 have been impacted by the disaster, the United Nations has estimated, and initial assessments indicate an urgent need for drinking water.

Tongans worked for days at the airport trying to clear the runway of ash so that much-needed aid could arrive.

The work was painfully slow, with only a few hundred metres being cleared each day.

AFP