Australian military aircraft and vessels will be deployed to help emergency services in bushfire ravaged states of New South Wales (NSW) and Victoria.
Thousands of people fled to beaches in the south-eastern states on Tuesday as emergency-level fires spread.
In Mallacoota, Victoria, about 4,000 people sought shelter on the coast.
Two more people have been confirmed dead in NSW, bringing the fire-linked death toll to 12.
Authorities say four people are missing in Victoria and another in NSW.
“We’ve got literally hundreds, thousands of people up and down the coast, taking refuge on the beaches,” said Shane Fitzsimmons, commissioner of the NSW Rural Fire Service.
Mr Fitzsimmons said it was “the worst fire season we have experienced here in NSW”.
Prime Minister Scott Morrison and Defence Minister Linda Reynolds have agreed to send military aircraft and vessels at the request of the Victorian government.
The military is expected to provide humanitarian assistance and carry out evacuations if needed in the coming days.
The US and Canada have also been asked to provide “specialist aviation resources” to help the emergency effort.
About a dozen “emergency-level” blazes stretch across NSW and Victoria.
Several holiday spots along the coast have been cut off and the main road in the region – the Princes Highway – has been closed.
At midnight on Tuesday, Sydney’s A$6m (£3.1m; $4.2m) fireworks display, renowned worldwide, went ahead despite calls for it to be cancelled given the scale of the bushfire crisis.
Temperatures exceeded 40C (104F) in every state and territory at the start of the week, with strong winds and lightning strikes bolstering the flames.
Meteorologists say a climate system in the Indian Ocean, known as the dipole, is the main driver behind the extreme heat in Australia.