Tonga is expected to issue specific requests for Australian help on Tuesday as more insight into the country's devastation from a volcano eruption comes to light.
British charity worker Angela Glover is the first confirmed death from the natural disaster, after an underwater volcanic eruption sparked a tsunami on Saturday and blanketed the Pacific nation in ash.
New Zealand officials believe three people have been killed.
Foreign Minister Marise Payne confirmed she is in communication with Australia's High Commissioner to Tonga Rachael Moore and that Ms Moore had been in contact with the Tongan prime minister.
"He is very grateful for Australia's assistance, and also of New Zealand. We are expecting them to set out their specific requests today ... they have had a cabinet meeting," Senator Payne told 2GB on Tuesday afternoon.
"The high commissioner has assured me that the government of Tonga is bringing everything together in this response."
All Australians have been accounted for in Tonga following the disaster.
There are normally about 300 Australians living in Tonga, but the number is estimated to be less due to COVID-19.
HMAS Adelaide is ready to take humanitarian supplies including engineering and medical personnel and equipment, as well as helicopters to aid with distribution.
The supplies will be deployed as early as Wednesday and the ship will take around five days to reach Tonga from Brisbane.
Two more surveillance flights - a P-8 and C130 - departed Australia on Tuesday morning.
New Zealand is sending the HMNZS Wellington and HMNZS Aotearoa.
Pacific Minister Zed Seselja said critical supplies such as food and water as well as communications and clean-up equipment will be sent on a C-130 plane once the airport in Tonga is able to reopen.
"There is still a significant amount of ash at the airport. It was hoped the airport might open today, but that's more likely now to be tomorrow," Senator Seselja told the Nine Network.
"We've offered $1 million in assistance at the moment, we're looking to hear back from the Tongan government in some more specific detail."
Initial data from a surveillance flight has come through and was shared with Tonga, with on-ground efforts also being carried out by Tongan authorities.
Tongan officials have warned the death toll from the volcanic eruption and tsunami in the Pacific nation is only set to grow, as damage assessment begins.
The deputy head of mission at Tonga's high commission in Australia, Curtis Tu'ihalangingie, said there was still uncertainty about the level of damage to Tonga, but basic supplies were needed.
"At this point (Tonga needs) water and also masks," he said.
"The county was covered with volcanic ash and this is very alarming and dangerous, not only for young children but for everyone."
A major underwater telecommunications cable was also damaged in the tsunami, and is expected to take at least two weeks to repair.
Mr Tu'ihalangingie said it would still be weeks before communication was fully restored in the country.
"Communication is on locally, so people can call one another in Tonga, but can't call internationally, we still have limited access to Tonga," he told ABC Radio.
"We still don't have a direct communication with our government."
Australia is also making available satellite connectivity from the high commission to support government communications and telecommunication companies to re-establish connections.
With Tonga enforcing a strict border measure to keep coronavirus cases out of the country, there are fears international aid efforts could lead to Tonga losing its COVID-free status.
"As much as we are going to send assistance, we will still need to follow the COVID-19 protocols to keep the people in the population safe, rather than us setting a system and there's a tsunami of COVID hitting Tonga, Mr Tu'ihalangingie said.
"We hope to maintain that and we're very appreciative of the understanding of the Australian government and partners."
