The Australian Broadcasting Corp. said lightning sparked the blaze more than a week ago.
A strong southerly wind is now expected to push the fire back into the bush, not into residential properties, the Australian broadcaster reported.
Officials said residents in Mount Hotham, Hotham Heights and Dinner Plain have been told not to evacuate.
The Country Fire Authority said the fire has not come close to homes or damaged any property, but an emergency alert was issued after the fire broke the agency's containment lines.
Officials said spot fires from the blaze are also a threat, and teams are working to control them.
Up to 250 firefighters are expected to work through the night, the Australian Broadcasting Corp. reported.