Screwdriver bandit in spate of hold-ups

A bandit armed with a screwdriver has terrified service station workers in Melbourne's east overnight.

Police say the man robbed three 7-Eleven stores, and in a bizarre move paid for a sandwich along the way.

The thief began at around 5.30pm when police say he used a screwdriver to threaten staff and steal cash at a convenience store on the corners of Waverley and Huntingdale Roads, in Mount Waverley.

The man then carried out a similar armed robbery at a convenience store at the corner of Waverley and Batesford Roads in Malvern East, police say.

Police then believe the culprit returned to the first store in Huntingdale Road and robbed it again.

At one store, CCTV footage shows the alleged thief buying a sandwich before he threatens the shop attendant.

He then travelled some 5km and held up a convenience store in Blackburn Road, Glen Waverley, at 2.30am.

It is alleged the man captured in the footage threatened staff with the screwdriver and stole cash during each raid.

Police believe he might be responsible for as many as seven robberies over the past week and they've vowed to increase their patrols of the area.

He is described as Caucasian, in his thirties, 175-180cm tall, slim build and bald.

He was wearing a black top and dark pants.

Anyone with information is asked to call Crime Stoppers on 1800 333 000.