Impact assessment, aid efforts underway as world responds to Tonga tsunami

* New Zealand reconnaissance flight on way to Tonga

* Red Cross says scale of devastation could be immense

* UN on standby to offer support

* Ash clouds from eruption moving towards NZ, Australia

By Praveen Menon

WELLINGTON, Jan 17 (Reuters) - Pacific nations and aid agencies began coordinating relief efforts in Tonga on Monday after a tsunami triggered by a massive volcanic eruption rocked the tiny island nation, causing significant damage.

An underwater volcano off Tonga erupted on Saturday, triggering a tsunami on the shores of Tonga and cutting off phone and internet lines for the entire island.

There are no official reports of injuries or deaths in Tonga as yet but communications are still limited and outlying costal areas remain cut off.

A New Zealand Air Force P-3K Orion aircraft left from Auckland on Monday to assist in an initial impact assessment of the area and low-lying islands, the New Zealand defence forces said on Twitter.

New Zealand's Prime Minister Jacinda Ardern said on Sunday that the tsunami had a significant impact https://www.reuters.com/world/asia-pacific/new-zealand-pm-ardern-says-tonga-eruption-hugely-concerning-2022-01-15 on infrastructure.

Red Cross said it was mobilising its regional network to respond to what it called the worst volcanic eruptions the Pacific has experienced in decades.

“From what little updates we have, the scale of the devastation could be immense, especially for outer lying islands," said Katie Greenwood, IFRC’s Pacific Head of Delegation.

“Red Cross currently has enough relief supplies in the country to support 1,200 households with essential items such as tarpaulins, blankets, kitchen sets, shelter tool kits and hygiene kits,” she said.

The agency said there were concerns that communities may not have access to safe drinking water as a result of saltwater inundation caused by the tsunami waves and ashfall.

Shelter is also a concern, particularly for those communities near the coastline, it added.

United Nations Secretary General Antonio Guterres said on Twitter that the UN offices in the Pacific are on standby to provide support.

MASSIVE BLAST

The Hunga-Tonga-Hunga-Ha'apai volcano has erupted regularly over the past few decades but the impact of Saturday's eruption was felt was far away as Fiji, New Zealand, the United States and Japan. Two people drowned off a beach in Northern Peru due to high waves caused by the tsunami.

About 26 hours since the eruption, nations thousands of kilometres to the west have volcanic ash clouds over them, New Zealand forecaster WeatherWatch said in a statement.

Fiji, Vanuatu and New Caledonia are affected and the ash cloud is expected to fan out towards eastern Australia on Monday, it said.

Early data suggests the volcanic eruption was the biggest blast since Mount Pinatubo in the Philippines 30 years ago, New Zealand-based volcanologist Shane Cronin told Radio New Zealand.

"This is an eruption best witnessed from space," Cronin said.

"The large and explosive lateral spread of the eruption suggests that it was probably the biggest one since about the 1991 eruption of Pinatubo," Cronin said.

(Reporting by Praveen Menon Editing by Nick Zieminski)