No one was injured after a man in pajamas robbed a Dundas bargain store with a pocket knife.

Hamilton Police say the man went into the Dollarama at 90 Main Street in the Town Centre Plaza at 6 p.m. Wednesday. Face covered, he approached the woman at the cash register who was alone in the store at the time.

Police say he pulled out a small pocket knife and demanded cash.

The employee struggled to get the register open, investigators say, and told the robber she needed a key to get it open. When she went to retrieve the key, the suspect was scared off and fled the store.

Police watched the surveillance video at the location and are working to identify the suspect.

He's described as white, five-foot-two, wearing a black balaclava, black shoes, a beige coloured sweater and blue pajama pants.

Anyone with information is asked to call the BEAR unit at 905-546-3849.