Officers were called to Caines Jewellers at 9.14am after three male suspects threatened staff with a firearm and hammers.
The suspects who, were all wearing black with face coverings, are thought to have left the area in a blue Subaru Impreza vehicle.
This has been recovered from nearby Walton Road where the suspects are thought to have left the area in a white BMW 1 series vehicle.
At this stage there are not believed to be any injuries and police are asking anyone who may have seen either vehicle in the area either prior to or immediately after the robbery took place to come forward.
A number of areas have been sealed off while investigations continue.
Anyone with information is asked to contact Stainbeck CID via: 0845 60 60 606.