See the judgment from the Supreme Court in NJA 2016 s. 264.
Hänvisas från p. 2 (s. 653)
2.The arbitrators’ Kompetenz-Kompetenz under Swedish law is not limited merely to determining the validity or scope of the arbitration agreement and its application to the instant dispute. The arbitrators also possess authority to recognise or refuse to recognise their jurisdiction on grounds other than those related to the arbitration agreement. For example, the matter in dispute may be non-arbitrable. The arbitrators may, e.g. also consider an objection that a successor to a contract has only assumed certain rights or obligations under the contract without becoming a party to the arbitration agreement. The arbitrators also have authority to decide on the existence of impediments to the arbitration and if the tribunal has been validly constituted and has thereby achieved competence. This latter determination may involve issues such as whether the arbitration has been initiated in the correct manner by a party, whether the arbitrators are qualified and are impartial and independent or if a correct number of arbitrators have been appointed.s. 653