Business experts fear that a break-in at a cash depot in Sweden could lead to a shortage of bank notes in circulation in the Stockholm region.

An undisclosed amount of money was taken when a gang used a helicopter to break into the cash depot.

The armed robbers landed the helicopter on the roof of the depot and allegedly blew a hole in the building to gain entry.

Two explosions were also heard coming from inside.

A large amount of cash was being stored on the top floor of the G4S security building, which was due to be used to fill ATMs in Stockholm for the coming weekend.

The robbers escaped in a helicopter stolen from a local airport, which was later found by police.

Police efforts in apprehending the raiders were slowed when a suspicious packet, with the word 'bomb' written on the side, was discovered next to the helicopter hanger, preventing the take-off of a police helicopter.