The Australian navy was racing on Friday to rescue thousands of people stranded on the east coast of the fire-ravaged country as a searing weather front was set to whip up more blazes across the states of Victoria and New South Wales (NSW).

The premier of Victoria, Daniel Andrews, declared a state of disaster for the first time ever, giving authorities broad powers to compel people to leave their properties and take control of services.

Wildfires have already killed two in the state and 17 are missing with grave fears for their safety.