The resort, in Victoria province, had not planned to open before June and the new date is five weeks ahead of schedule. It's the area's earliest opening in its 45 year history.
The opening is the result of unseasonably cold weather which brought up to 50cm (20 inches) of snow to many of Australia's ski fields (Buller has 35cm/14 inches), although currently there are no reports of any others planning to follow Mt Buller and open early.
The resort's new six-seat chairlift serving the Bourke Street trail will be open on Saturday and Sunday with lift tickets costing $20.
"It's the best snow we've had this early since 1964, so it's pretty huge for us," Mt Buller spokeswoman Gillian Dobson told local media.