This paper explores the role and application of soft law in international arbitration procedure. It acknowledges the ongoing debate surrounding the normativity of soft law instruments but asserts their acceptance and use in practice. It examines the necessity of soft law in procedure, arguing that while lex arbitri and institutional rules provide flexibility, they often lack the detailed guidance needed for efficient proceedings. Thus, soft law instruments fill this gap, providing predictability and consistency based on international best practices. The paper identifies the sources of a tribunal’s power to apply soft law under the UNCITRAL Model Law and the arbitrator’s contract. It discusses when tribunals should resort to soft law, suggesting that seeking consensus among parties is ideal. However, in its absence, the tribunal can declare the applicable instrument, ideally in the first procedural order, to avoid the award being challenged by parties on the ground of ‘surprise’. Finally, the paper compares the IBA Rules and Prague Rules, noting their convergence despite different philosophies, and concludes that the choice of instrument is a discretionary matter for the tribunal, akin to a craftsman selecting tools, to be guided by the nature of the dispute while adhering to due process.
Arbitration: The International Journal of Arbitration, Mediation and Dispute Management