Firefighters battling bush fires around the Australian city of Sydney have received a respite from the ferocity of the blazes after clouds gathered over the city for the first time in days.

Searing temperatures have dropped, but with erratic winds blowing and no rain in sight, Australia's fire crisis has entered its 12th day.

More than 50 bush fires are raging around the state of New South Wales today, including one only miles from Parliament House in Canberra.