The earthquake happened about 09:15 local time (23:15 GMT) on Wednesday at Mansfield, not far from the Victorian state capital.
Prime Minister Scott Morrison said “we have had no reports of serious injuries and that is very good news”.
The earthquake was also felt in neighbouring South Australia and New South Wales (NSW).
It was followed by two aftershocks of 4.0 and 3.1 magnitude.
While this is one of Australia’s largest earthquakes in recent years, it does not appear to have caused significant damage.