Man remains missing after Victorian factory fire

A Victorian man remains unaccounted for as fire fighters continue to black-out the smouldering remains of a central Victorian steel factory that caught fire.

Emergency services have not been able to locate the man who lived at the Seymour site since being called there about 2.15am.

Fire crews arrived to find the factory engulfed in flames.

Police say they don't know whether the man was in the factory at the time of the fire and the cause of the blaze remains unknown.

A CFA spokeswoman said firefighters are still at the scene.

"There's still crews there," she said.

"It will smoulder for quite some time."