The principal source of the powers of an arbitral tribunal is the arbitration agreement itself and therefore the mandate of the tribunal stems from the agreement of the parties.
The arbitration agreement may confer powers on the arbitral tribunal expressly for instance if the arbitration agreement itself stipulates expressly that the tribunal or the arbitrator will have power to give an interim or provisional relief. If the arbitration agreement provides that the Arbitration Act will apply then the extensive powers given under that Act again will be available to the Arbitrator.
The powers are stemming from the Agreement of the parties. The parties are the ones conferring the powers on the arbitrator through the arbitration agreement i.e. powers to determine procedure , powers to determine the venue , power to give the award , power to rule on jurisdiction.
If the agreement incorporates the rules of an institution for instance the arbitration rules of the chartered institute of arbitrators again the powers that are conferred under those rules would be available to the tribunal.
Under Clause 16 of Chartered Institute of Arbitrators Rules , the tribunal has jurisdiction to determine the extent , validity or existence of an agreement which is essentially an adoption of Section 17 of the Arbitration Act. There is power under that clause to allow an amendment of the arbitration agreement itself. If for instance the arbitration agreement has an error , tribunal has power to rectify such error. Under the same clause there is power to decide on questions of law. there are powers to decide on question of dishonesty , fraud or bad faith arising in the dispute , there is power to order parties to furnish further details of claims , there is power to make an order for conservation of property , power to order parties to make interim payments towards the cost of arbitration. Power to order payment of interest etc.
To a large extent the rules summarises the powers found in the Arbitration Act but the overriding principle is that the tribunal has those powers conferred on it by the parties.