A massive 170 square kilometre wind farm has passed the final Victorian planning hurdle, and could be powering in four years if the federal government approves the project.

The $1.5 billion wind farm, sprawling over 17,000 hectares near the small town of Rokewood south of Ballarat, passed environmental approvals last month.

Acting Planning Minister Lily D’Ambrosio will on Saturday announce the Victorian government has granted a planning permit for the project in the Golden Plains Shire.

All that remains is for the federal government to sign off on it.