Five non-governmental organisations have been given permission to file amicus curiae briefs in the arbitration Biwater Gauff (Tanzania) Ltd v United Republic of Tanzania (ICSID Case No ARB/05/22). This is understood to be the first occasion on which an ICSID tribunal has permitted non-parties to file amicus submissions under the revised ICSID Arbitration Rules, which now expressly provide for a tribunal to permit non-parties to file written submissions.

The order, made on 2 February 2007, reflects the growing trend towards transparency in investor-state arbitrations, which often raise issues of public importance. Shortly after the order was made in this case, on 12 February 2007, a different tribunal in the arbitration Suez and Others v The Argentine Repbulic (ICSID Case No ARB/03/19) (see Legal update, ICSID tribunal permits amicus curiae brief: Suez v Argentina), gave permission to certain non-parties to file amicus curiae briefs. That case has been proceeding under the previous ICSID Arbitration Rules, and the discretion was exercised pursuant to a power which the tribunal found it had under the ICSID Convention to permit amicus curiae submissions. In that arbitration, the tribunal acknowledged that allowing such submissions was an important element in the overall discharge of their mandate, and in securing wider confidence in the arbitral process itself.