Firefighters in Australia warned Tuesday they would not be able to contain some of the 100 fires still ablaze in the country before conditions are expected to deteriorate later this week.

Temperatures across parts of the eastern state of New South Wales (NSW) are expected to top 40 degree Celsius (104 Fahrenheit) on Wednesday, just shy of a record high for Australia's most populous state.

With bushland tinder-box dry, authorities warned locals near existing blazes that fires could spread.