Aid agencies are at the ready to help disaster-hit Tonga, but say downed communications are slowing the relief response.
Three people have been confirmed dead in Tonga following Saturday's volcanic eruption and tsunami, as aerial images show catastrophic damage to the island of Mango and extensive damage to other islands in the Ha'apai group .
Two New Zealand navy ships have left for Tonga carrying urgent supplies like clean water, emergency provisions, and diving teams to survey the shipping channels and ports.
Aid agencies have described the communication situation in Tonga as "absolutely terrible" while the critical undersea cable, that connects Tonga to the world, could be offline for weeks.
Save the Children chief executive Shairana Ali said getting information on the ground had been incredibly challenging.
She said international aid groups would send satellite phones from Fiji to aid workers in Tonga once it was safe for planes to land in the capital.
"Then at least, there is a more reliable way of being able to communicate about the situation," she said.
Defence Minister Peeni Henare has warned it could be Thursday before Tonga's main runway was cleared of ash to allow planes carrying supplies to land.
Massey University professor of construction management Suzanne Wilkinson said as well as posing health risks, the ash will require huge efforts to clear.
"There's a lot to be done in terms of the waste of the ash, the impact of the ash and the disposal of the ash.
"They might need some big machinery, for instance, to clear the road.
"It's about, do they have the capacity and capability to clean up? If not, then that's an ideal area for us to focus on."
New Zealand could provide goggles, face masks and protective clothing to keep people safe as they clear the volcanic debris, she said.
There is also concern about the mental wellbeing of Tongans needing relief in dire circumstances.
Associate professor at Massey's school of psychology Siautu Alefaio-Tugia said people need support now.
"It will be really around the trauma of losing everything," she said.
"I'm thinking of having been in Tonga and doing a lot of disaster preparedness work over the last four years, prior to Covid, and the families who hosted us, who literally ran for their lives through the bushes, and now only had the clothes on their backs."
Alefaio-Tugia said psycho-social recovery in Tonga needed to be community-led.
"It needs to come from Tongan leaders themselves, because they have their own connections," she said.
"It would be the Tongan diaspora that I would encourage working with, because they are the ones that are going to sustain those communities, long after the humanitarian agencies and first responders have left."
"I think we need to really focus on the support that the Tongan leaders in New Zealand might need."
Massey University professor of disaster management David Johnston said a slew of natural disasters in Tonga had left some residents traumatised and the aid needed to extend beyond the latest event.
"They've had previous cyclone events, they're in a Covid crisis, there's climate change, there's been other natural events in the past, so that's become, to some degree, cumulative on individuals and their communities," he said.
"These events are nested together, they're not in isolation."
He said it will be crucial to lean on trusted community leaders.
"A lot of the support that people need in a disaster comes from the community itself, those around them," he said.
"Yes, there is obviously some specialist support that can be provided, but most communities do have the capability and capacity to support their members, if people are safe and secure in their housing and their location."
In New Zealand, people have been rallying to organise supplies to send to Tonga.
Volunteer charity worker Paul Simmons, from Rapid Relief Team New Zealand, said when he saw the pictures of the devastated Tongan islands he thought water supplies would be needed.
He called up Alpine Drinks, which bottles water from Hawke's Bay, who put the job at the top of their list. "We've got a load of 12,672 water bottles ready to go and we've also got 350 personal hygiene kits made up, which we had in stock, so we're going to see those as well," he said.
The supplies are being sent to Auckland today and hopefully on the next supply run to Tonga.
Meanwhile the newly-established Aotearoa Tonga Relief Committee is calling for donations of containers and goods to send to families in Tonga.
Jenny Salesa, local MP for Panmure-Ōtāhuhu and the co-chair of the committee, said the group was coordinating care packages to send to Tonga from families in New Zealand.
The care packages will be sent to village chiefs who would then distribute these to families without connections to New Zealand.
"Our committee is voluntary, we do not have any resources at this time and we would gladly accept donations of containers at no cost please so that we can help families in Tonga," she told Morning Report.
"This is work that we have done, this is what families overseas usually do when natural disasters hit in the Pacific."
The containers would be filled with groceries and food like flour, rice and sugar.