Langi Fatanitavake's wife and son live on one of the islands flanking Tonga's Hunga Tonga-Hunga Ha'apai volcano, but his repeated calls home since the violent eruption and tsunami have gone unanswered.
The South Island seasonal worker last spoke to his family on Ha'apai on Saturday afternoon, shortly before destructive waves crashed into the island nation.
Fatanitavake is growing increasingly concerned for their safety.
"Last night and today, nothing. I called, no answer. My feeling is not good about my family," he said.
Fatanitavake is also worried about his sister who lives on Atata Island, about 50 kilometres from the volcano that has covered Tonga in a layer of ash.
"I want to know what happened to my sister," he said.
Fatanitavake said the 17 other Tongans he was working with on an Alexandra orchard had not heard from their families either and were anxious to receive a simple message or phone call to say they were safe.
A repatriation flight scheduled for Thursday for workers who came to New Zealand as part of the Recognised Seasonal Employers scheme has been postponed.
Tongans in New Zealand have been praying for their Pacific Island families, as they endure an agonising wait for news from relatives cut off from the world.
Timaru's Sina Latu last heard from her sister when she broadcast her family's escape from the tsunami live on Facebook, as ash rained down on the island of 'Eua.
"It was very scary, we could see the waves coming in," she said.
While Latu believed they were safe, she said the lack of communication was upsetting.
"It's painful, you just feel hopeless and very anxious," she said.
"I'm so worried, I haven't really slept well. I just want one phone call, or one message, that will do me, just to say we're fine, we're safe."
Latu said she was also worried about her 80-year-old father who lives on Tongatapu, but was reassured by no official reports of injuries or deaths so far.
A New Zealand Defence Force plane has flown to Tonga to assess the damage, but Prime Minister Jacinda Ardern said aerial reconnaissance depended on the conditions, including the amount of suspended volcanic ash.
Another plane will take essential supplies like water later today.
Communication links were still down, because the undersea cable that connects Tonga to the wider world appears to have been damaged.
Invercargill's Ofa Boyle is yet to hear from her brother and sister who live near the capital Nuku'alofa.
She is also worried about the situation on the Ha'apai group of islands.
"I have some extended family living around that area, in Ha'apai. It's a big worry," she said.
"On the main island, the waves coming inland are not those big giant ones. That gives a bit of relief, but I'm also anxious about what it's like in other areas like Ha'apai, near where the volcano erupted."
Boyle said Tongan families relied heavily on relatives overseas, who would rally around to help them.
GNS Science said there could be more small-scale eruptions for some weeks, but they would be unlikely to trigger another big tsunami.