Two New Zealand Defence Force aircraft are heading to Tonga, with one set to drop urgent supplies and the other to make an assessment of the situation.
It comes after Tonga was hit by a tsunami following a large eruption of the Hunga-Tonga-Hunga-Ha'apai underwater volcano on Saturday. Communication with Tonga has been limited due to power cuts and an undersea communications cable that was impacted.
New Zealand's Hercules plane was preparing to depart for Tonga to make provision drops, "regardless of what the airport is looking like," Prime Minister Jacinda Ardern said, while the Orion aircraft's arrival in Tonga was "imminent".
"It is, as are the Australians, looking to take an assessment from the air of the outer islands in particular and then provide that information to the people of Tonga."
NZDF provided an update on Monday afternoon, saying the Orion was due to arrive back in Auckland this evening after flying over the Ha’apai group of islands, then over Tongatapu to check the runway and port.
The Hercules was on standby to fly with aid supplies on Tuesday if the runway was safe.
"Royal New Zealand Navy ships are being readied for deployment and may deploy ahead of a formal request for assistance, given the distance to Tonga," NZDF said in a statement. "Further military flights are also possible, to transport relief supplies and personnel as required."
Ardern said earlier she had been advised Tonga had also dispatched people by sea to make assessments of the outer islands.
"For the C130 Hercules, we are planning to enable drops to be undertaken regardless of the status of the airport."
Ardern said the C130 Hercules "will be able to meet immediate supply needs", but having a wider assessment would let them know the equipment required to have on board should they send a navy vessel over.
"Ash cloud does pose a risk, but the view on departure was that they would be able to undertake that over flight reconnaissance and provide that really critical information back."
Defence Minister Peeni Henare said that "making sure we have the necessities on board to make sure they that Tonga can recover the best it can, and that can only come from right information from Tonga".
"We're confident with the limited communications and the work of the Orion, in partnership with the Australian Defence Force... we'll have a far better assessment of the need of those places."
He said Nuku'alofa was "coming back into operation", with power being restored in large parts, but there was a need for urgent supplies such as water which the Hercules aircraft would drop.
Henare said once the assessment of needs was completed, New Zealand could continually fly to Tonga and back to help.
Henare did not have a estimated time on when people would be able to communicate with their family in Tonga, but said some had found a connection and we reporting to officials about what they were hearing was happening on the ground.
The Defence Minister also apologised for posting a picture of himself at the gym with the caption: "Our thoughts are with the whānau in Tonga. We have the team working hard to respond. More on that soon. In the meantime."
"I apologise if my picture offended anyone," he said today. "What was advertised on that picture too was that I encouraged people to tune in to the 3pm (press conference) where the Prime Minister, myself and Minister Sio gave more details and more updates on the situation in Tonga."