A new search of Mount Macedon will begin on Thursday as fresh information comes to light in the murder of Melbourne woman Karen Ristevski.

The development comes after witnesses reported seeing a black Mercedes-Benz like the model owned by Ms Ristevski in the Mount Macedon area on the day she went missing.

The search will follow the route detectives believe may have been taken to the location in Macedon bushland where Ms Ristevski's body was dumped.

One witness told investigators a lone male was also seen near the car.