The cars at the Olympic Park Aquatic Center at Homebush caught fire Saturday as families swam, the Australian Broadcasting Corp. reported.
The fire was started by a grass fire and was strengthened by strong winds.
Authorities said they evacuated about 500 people from the swimming center before the fire was contained.
No one was injured, the ABC reported.
Firefighters are also attempting to halt two other bush fires in New South Wales, where five homes have already been destroyed.
Authorities are setting up containment lines and are hoping that a change in the wind will move the blaze away from properties.