Yes. Arbitrators have the obligation to provide each party with a reasonable opportunity to present its case, including evidence, in conditions that do not place it at a substantial disadvantage vis-à-vis its opponent. This is known as the principle of equality of arms.
This principle enabled the Paris Court of Appeal to set aside an arbitral award in a judgment dated 8 November 2016. The Court of Appeal considered that in the present case, one of the parties, namely the Government of the Republic of Iraq, had been unable to prepare its defense, as it was in a state of war at the relevant time, which placed it in a "substantially disadvantageous position with respect to its opponents."
It should be well noted that the party requesting the annulment of the award had already raised before the arbitral tribunal that it was not in a position to effectively prepare its defense.
The Court therefore recalled that the arbitral tribunal was bound to adapt the duty of celerity to the factual situation to secure the fairness of the proceedings. Indeed, the duty of celerity (which can be found in Article 1464 (3) of the French Code of Civil Procedure) is not absolute and is overridden by the requirement that the parties must be in a situation of substantive equality and not only formal equality.
The principle of equality of arms, which is an element of due process, is part of international public policy. As this principle had not been respected, the arbitral award was set aside for violation of international public policy.
Judgment cited: Paris Court of Appeal, pôle 1, Chamber 1, 8 November 2016, no. 13/12002