25. Competence of arbitral tribunal to rule on its jurisdiction

(1) Unless otherwise agreed by the parties, the arbitral tribunal may rule on its own substantive jurisdiction, that is, as to (a) whether there is a valid arbitration agreement, (b) whether the tribunal is properly constituted, and (c) what matters have been submitted to arbitration in accordance with the arbitration agreement.
(2) Any such ruling may be challenged by any available arbitral process of appeal or review that the parties may have agreed, or in accordance with the provisions of this Part.