Three teens have been arrested and three youths remain on the run after locals were terrorised in a spate of violent armed robberies near university campuses in Melbourne's south-east.

The spree began on Stockdale Avenue near Monash University's Clayton campus about 7pm on Wednesday, when three youths approached a man and demanded his bag and phone.

The 25-year-old local man, and Monash University student, was struck in the face with an object, receiving minor injuries.

The offenders, described as African in appearance, then fled the scene with the victim's possessions.