The plea of institutional or contractual arbitration (arbitrato irrituale), relating as it does to the merits and not to competence, is subject to the procedural regime governing defences of a substantive nature and cannot be raised by the court of its own motion, but must be expressly raised by the party.
Pursuant to Article 808-quater of the Code of Civil Procedure, in cases of doubt the arbitration agreement is to be interpreted as extending arbitral jurisdiction to all disputes arising from the contract or the relationship to which the agreement refers, so that, absent an express contrary intention, the arbitration clause is to be interpreted as referring to arbitral jurisdiction all disputes whose causa petendi lies in the contract to which the clause is annexed.
In the case of contractual arbitration (arbitrato irrituale), which constitutes a means of resolving civil disputes that is alternative to and outside the judicial sphere, the court must declare the claim inadmissible, the parties having consensually excluded the possibility of recourse to the ordinary courts, without Article 819-ter of the Code of Civil Procedure applying and without any time limit for recommencement before the arbitral body to be constituted being fixed.