Robber gets smashed in hold-up

A quick-thinking shopper in a Canberra supermarket saved the day by smashing a bottle of red over a would-be robber's head, thwarting an armed hold-up.

The hooded bandit threatened staff with a knife at the shop in the northern suburb of Cook about 6.40pm on Thursday.

"As he made the demands, a customer boldly struck the offender on the back of the head with a full bottle of red wine," police said in a statement.

Security camera footage shows the bottle smash, leaving the robber stumbling before he runs off without any loot.

The wine headache didn't deter the robber who is believed responsible for two subsequent, but failed, shop hold-ups in nearby suburbs over the next 30 minutes.

On the second occasion he was scared off when a car pulled up outside and on the final attempt staff refused to hand over cash, police said.

The offender is described as about 170cm tall, of average build, aged in his 20s, and wore a dark hooded jacket at the time of the hold-ups.

He probably also reeked of wine.