Plans to launch Iron Maiden's own brand of beer in Sweden have suffered a setback amid concerns the drink's label violates the nation's strict alcohol laws.

Sales of the rockers' new Trooper ale, which features a picture of their skeletal mascot Eddie the Head on the label, have been halted in government-owned liquor stores Systembolaget, according to local reports.

Company spokesperson Therese Elmgren says, "There has been a discussion about the label. The alcohol law stipulates how it can look. We therefore don't yet know when it can be launched."

The heavy metal stars' beer has proven popular around the world - the brewer of the drink recently stepped up production to six days a week to meet demand from more than 100 countries.