Man arrested over armed car thefts in Vic

A South Australian man has been arrested after allegedly stealing a woman's car armed with a knife in western Victoria before using a sledgehammer to try and take a second vehicle.

The 34-year-old pulled the knife on the woman at her Concongella property early on Tuesday morning before driving off in her Holden Captiva, police said.

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

The South Australian was arrested at nearby Bealiba on Tuesday night, allegedly while trying to steal another car and assaulting the owner.