Armed man terrorises Victorian car owners

A man is on the run after arming himself with a knife to steal a woman's car and later using a sledgehammer to try and take another vehicle in western Victoria.

The suspect, thought to be his 30s or 40s and wearing dark clothing, pulled a knife on the woman at her Concongella property early on Tuesday morning before driving off in her Holden Captiva, police said.

He threatened another man with a sledgehammer at Rathscar before being chased away and dumping the Holden in a paddock.