As catastrophic fire warnings remain in place in northern Victoria, Melbourne may have recorded its hottest overnight temperature on record, with a minimum of 32.3 degrees Celsius.
The previous record of 30.6 degrees was set in February 1902, the ABC reports.
Peter Blake from Australia's weather bureau says for most of the night the temperature was above 34 degrees.
The bureau was to decide later on Tuesday whether to declare a new record.
Inland areas of New South Wales are also under catastrophic fire warnings as temperatures were again expected to top 40 degrees on Tuesday.