Tasmanian police want to speak to the occupants of a blue car who arrived at a drive-through bottle shop in Hobart's north while a robbery was taking place.

Two masked men armed with knives held up the Valern Hotel bottle shop in Moonah about 10:00pm on Saturday night while a third man kept watch outside.

Detective Senior Constable Daniel Lamont said CCTV footage showed a blue hatchback arriving at the bottle shop's drive-through while the robbery was underway.

"The male who's having a cigarette keeping a lookout has had some short discussion with the occupants and they've then left," the detective said.

The robbers threatened staff with 30cm carving knives and made off with cash, cigarettes and alcohol.

The first robber is described as being about 193cm tall, of thin build, wearing a black hoodie, a black balaclava, blue tracksuit pants with white stripes down the side and white sandshoes.

The second robber is about 165cm, of thin build, wearing a grey hooded top, a black balaclava, blue tracksuit pants and wearing white sandshoes.

Police are asking anyone with information to contact police or Crimestoppers on 1800 333 000.