The acting United Nations co-ordinator in the Pacific understands three people have died following the eruption in Tonga on Saturday.
Fiji-based United Nations co-ordinator Jonathan Veitch said two deaths were confirmed but there were still areas that had not been contacted.
He said one of those fatalities was British national Angela Glover, who was reported by her family to have been killed by the tsunami.
Glover is thought to have died trying to rescue her dogs at the animal charity she ran.
Veitch said help was on the way for the people of Tonga.
The Hunga Tonga-Hunga Haʻapai volcano, which erupted on Saturday, was about 65km north of Tonga’s capital Nuku’alofa
There is now a huge clean up operation in the town, which has been blanketed in thick volcanic dust.
Serious damage has been reported from the west coast of Tongatapu and a state of emergency has been declared.
Acting High Commissioner for New Zealand in Tonga Peter Lund told Tagata Pasifika he could see rubble, large rocks and damaged buildings, with serious damage along the west coast of Tongatapu.
“There is a huge clean-up operation underway, the town has been blanketed in a thick blanket of volcanic dust, but look they’re making progress… roads are being cleared,” he said.
Meanwhile, the United Nations say a distress signal has been detected in an isolated group of islands in the Tonga archipelago following Saturday’s volcanic eruption and tsunami, prompting particular concern for its inhabitants.
The UN Office for the Coordination of Humanitarian Affairs said there had been no contact from the Ha’apai group of islands and there was “particular concern” about two small low-lying islands – Fonoi and Mango, where an active distress beacon had been detected.
According to the Tonga government, 36 people live on Mango and 69 on Fonoi.