PNG's National Disaster Centre said more than 2000 people had been buried alive by Friday's landslide in remote Enga province.
Australia will send technical experts and $2.5 million in initial aid to PNG as the death toll continues to rise following the catastrophic landslide.
Under the Australian aid package experts will provide incident management assistance, support geo-hazard assessments and help early recovery efforts, with the Australian Defence Force also assisting.
"As a close neighbour and friend, we will be doing all we can to provide support," Deputy Prime Minister Richard Marles said in a statement late on Monday.
Villagers search through rubble after a deadly landslide in PNG. (AP PHOTO)
Treacherous terrain in the region and difficulty getting in aid has hampered rescue efforts, raising fears few survivors will be found.
Australia is ready to consider additional support beyond Monday's announcement, Foreign Minister Penny Wong said.
"(This) package will assist the urgent needs of those affected by this devastating landslide," she said.
The head of the International Organisation for Migration in PNG Serhan Aktoprak said the conditions on the ground were hampering rescue and aid efforts.
Rocks were still falling from the mountain, soil was cracking and water was flowing under the debris.
All Australians will be thinking of Papua New Guinea at this very difficult time.— Richard Marles (@RichardMarlesMP) The Australian Government will provide an initial $2.5 million in humanitarian assistance to support PNG's response to the landslide in Enga Province.May 27, 2024
"We're just hoping that in the remaining short window of time that we have, we can at least contribute to the relief efforts in saving some more lives," Mr Aktoprak said.
"But unfortunately, (time) is not on our side."
Mr Marles said Australia would continue to work with PNG officials as to how best to deliver aid.
A spokesperson for United Nations Secretary-General Antonio Guterres said he was "deeply saddened" by the reported loss of hundreds of lives.
"He extends his heartfelt condolences to the families of the victims and expresses his solidarity with the people and government of Papua New Guinea," the spokesperson said.
"The United Nations and its partners are supporting the government's response efforts.
