A Canberra customer has taken matters into his own hands during an attempted supermarket robbery last night, smashing the offender over the head with a full bottle of red wine.

Security vision from the supermarket at Cook, in the city's north, showed the would-be robber threatened staff with a knife, stumbled after the blow to the head, then ran away without any cash or property.

But the injury did not stop the man continuing on with his crime spree on Canberra's northside, and he robbed two other Canberra stores in the space of half an hour.

About 20 minutes after the first robbery at Cook, the man went to a supermarket in Scullin and threatened staff with a knife, but he was spooked and ran away when a car pulled up outside the store.

About 10 minutes later the man went to a business in Higgins, demanded money and threatened staff with a knife but ran off when staff refused to meet his demands.

Police are seeking witnesses to all three robberies, which did not net the offender any cash or property.