A passenger in a rideshare automobile seen the injured man in a gutter on the aspect of the Princess Freeway in Berwick, about 12.15am.
The passenger referred to as for police to assist the person who was between Neill and Peel streets.
Victoria Police consider the person is struggling life-threatening accidents after being hit by a automobile.
The Princess Freeway has been blocked off whereas police examine the scene.
Police are urging anybody who might have witnessed the incident to contact Crimestoppers on 1800 333 000.