The ministry said it had asked Brussels to class the products as drugs, based on a recommendation from public health authorities which identified 24 cannabinoids and seven cathinones as dangerous substances.
The Swedish government "is seeking a speeded-up procedure, meaning that the time that the European Commission takes to handle the ban is cut to 10 days instead of the usual three months," the ministry said yesterday.
Synthetic marijuana, known as Spice or K2, Yucatan Fire, Moon Rocks and Bliss, contains the same active element as natural marijuana, but it is far more toxic.
Several countries have already tried unsuccessfully to stop the sale of synthetic marijuana, which is supposed to be burned like incense rather than smoked.
Sweden has one of the most repressive policies in Europe on cannabis. Swedish law allows convictions for the use of drugs in private homes once the presence of the drug has been confirmed by a urine test.