Police said the armed men entered the business on High Street, Thornbury, just after 11am.

They stole a number of firearms, before fleeing the scene in a stolen car.

"We do not know the exact number of firearms stolen…but we do know they were handguns," Assistant Commissioner Stephan Fontana said during a press conference this afternoon.

The white SUV was found dumped a short time later on Clapham Street, about 5.7km from the crime scene.

Asst. Comm Fontana described the robbery as a "targeted attack" and could be linked to an organisation.

"It's a highly unusual offence," he said.

No one was injured in the incident.

Investigations are ongoing.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000