The warning came from Systembolaget's Finnish counterpart Alko, which has carried out tests on the drink, newspaper Aftonbladet reports. Customers who have bought bottles of the cinnamon-flavoured whisky can take the bottles back to Systembolaget, where they will get a refund.
It is not yet known how high the levels are, or if they pose a risk to public health. Systembolaget is now to carry out its own tests of the brand.
Products sold in the EU are only allowed to contain max 0.1g/kg of the substance, in the USA the limit is 5 grams per kilo.