An armed hold-up at a bottle shop in Melbourne's south-west has left a staff member too terrified to work after a shotgun was shoved in his face.

Police are searching for two men wanted over the terrifying theft at Williamstown on December 23, which was caught on CCTV.

Confronted by two men in ski masks demanding cash from the register, the bottle shop worker loads money into a duffel bag with a shotgun pointed at him.

The thieves were out of the shop in just 25 seconds.

The Williamstown bottle shop was held up on December 23.

Sergeant Damian O'Mahoney said this robbery was particularly violent.

"You can see the erratic nature of the man particularly with the shotgun who is moving around the store," he told 9NEWS.

"The way he threatens the staff member, it's completely irrational."

The thieves waved a gun directly at the bottle shop worker.

With guns in full view of witnesses, the robbers fled on foot up Douglas Parade.

Sergeant O'Mahoney said the worker was still struggling with the ordeal.

"He doesn't want to return to work, which is understandable."

This thief pointed a gun at staff at the 7/11 in Chapel Street.

It comes as police search for another armed robber who targeted a 7/11 in Chapel Street on Wednesday night.

Pointing a gun at terrified staff, the thief is seen on running away with $200 down Wilson Street. He is described as Caucasian, 175cm tall, with blue eyes and a medium build.