The economic cost of bushfires in NSW and the ACT will double to $200 million a year by 2050, according to a new report from the Climate Council.

It says climate change is causing the fire season to start earlier and last longer, with dangerous fire weather extending into spring and autumn.

Nationally, bushfires cost an estimated $375 million a year. That figure is expected to reach $800 million by mid-century.

The estimates take into account increases in the number of households, growth in the value of housing stock, population growth and rising infrastructure density.

But they do not incorporate increased bushfire incident rates due to climate change, and “could therefore be significantly higher”.

The report warns “this is the critical decade to protect Australians”.

“The only approach to keeping the risks from bushfires manageable is rapid and deep reductions in emissions,” the Climate Council says.