(3) If there are existing in any trade or industry any arrangements for settlement by conciliation or arbitration of disputes in such trade or industry, or any branch of trade or industry, made under an agreement between organisations of employers and organisations of workers representative respectively of substantial proportions of the employers and workers engaged in that trade or industry, the Governor General shall not, unless with the consent of both parties to the dispute, and unless and until there has been a failure to obtain a settlement by means of those arrangements, refer the matter for settlement in accordance with the foregoing provisions of this section.