Melino Maka hardly got any sleep overnight and has been trying "every few minutes" to reach friends and loved ones in Tonga.
Maka, who is chair of the Tonga Advisory Council in Auckland, says he feels "powerless, helpless" after tsunami waves swamped his home island nation on Saturday evening following a volcanic eruption.
He is one of many thousands trying to reach loved ones and friends, but main communication lines remain down on Sunday.
Waves struck about 6pm on Saturday (NZ time) and followed several eruptions of Hunga-Tonga-Hunga-Ha'apai, located about 30km south-east of Fonuafo'ou island.
The eruptions had been noted the preceding day, then the final eruption sent steam, ash and gas 20km into the air and could be felt as far as Fiji.
The underwater volcano has triggered tsunami warnings and evacuation orders in the United States and Japan and causing large waves in several South Pacific islands, where footage on social media showed waves crashing into coastal homes.
Tsunami waves were observed in Tonga's capital Nuku'alofa and the capital of American Samoa, a US-based tsunami monitor said, following the eruption.
New Zealand has issued a tsunami alert for the north and east coast of the North Island, the South Island's west coast and the Chatham Islands.
Maka said he had written to the new Tongan Prime Minister asking for directions on what to do next. The Tongan Government has yet to ask New Zealand for help.
"Many in the community have called me to ask what they can do to reach their families, they are worried just as I am, but I feel powerless and helpless because there's just nothing I can do," he said.
He had heard from the community that areas such as Patangata, Sopu, Popua and Fangaloto are underwater.
"So the footage that we are seeing are just the surface of how bad the situation is because people have not been able to send through videos or pictures now that much of the communication networks are still down," Maka said.
Social media footage that has been shared shows people fleeing in the dark.
"The biggest worry for most of us here is not knowing what happened to our families, and this again shows the vulnerability of Pacific Island nations when natural disaster strikes," Maka said.
"We are just getting really desperate for information."
New Zealand's Ministry of Foreign Affairs and Trade said late Saturday that it had no information to suggest Kiwis had been affected "at this stage".
"The New Zealand High Commission in Nuku 'alofa is monitoring the situation closely and is in contact with local authorities."
Attempts to contact the High Commission this morning by The New Zealand Herald had not been successful.
MFAT said all New Zealanders in Tonga are advised to register their details on safetravel.govt.nz. A spokesperson on Saturday night said 18 Kiwis were registered as being in Tonga with Safe Travel.
"If you are in the affected area or areas potentially affected by a tsunami you should follow the advice of the local authorities, including any tsunami evacuation orders. Please also keep your family back in New Zealand informed of your wellbeing.
"We also recommend that you stay informed of developments by monitoring local media. If you require consular assistance please contact the New Zealand High Commission in Nuku'alofa on +676 23122 or for consular emergencies +64 99 20 20 20."
- additional reporting by Reuters
