A wide band of rain sweeping New South Wales (NSW) has put out 20 of about 60 fires in the state in the past day.
Authorities have welcomed the downpour, but warned of flash flooding in Sydney and other cities along the coast.
Some of the affected areas had received the most rain recorded in over a year, said the Bureau of Meteorology.
Australia's largest city, Sydney, recorded its wettest day in over 15 months on Friday. Many locals cheered on the downpour despite the inconvenience.