The participation of intergovernmental organizations in the meetings of the Conference is governed by rule 16 of the rules of procedure of the Conference:
Rule 16
Participation of entities and intergovernmental organizations
1. Subject to prior written notification to the Secretary-General, representatives of entities and organizations that have received a standing invitation from the General Assembly to participate as observers in the sessions and work of all international conferences convened under its auspices, representatives of United Nations bodies, specialized agencies and funds, as well as representatives of functional commissions of the Economic and Social Council, shall be entitled to participate as observers in the deliberations of the Conference.
2. Representatives of any other relevant intergovernmental organization may also apply to the bureau for observer status, which shall be accorded unless otherwise decided by the Conference.
3. Without taking part in the adoption of decisions on substantive and procedural matters, whether by consensus or by vote, at the Conference, such entities and organizations may:
(a) Attend plenary meetings of the Conference;
(b) Deliver statements at such meetings at the invitation of the President in consultation with the bureau;
(c) Receive the documents of the Conference; and
(d) Submit their views in writing to the Conference.
Intergovernmental organizations that wish to participate in the meetings of the Conference and which are not listed in the Blue book, prepared by the Protocol and Liaison Service, Executive Office of the Secretary-General, or the Conference Room Paper "List of organizations" ( CTOC/COP/2010/CRP.7*) may wish to consult General Assembly decision 49/426 (1994) and General Assembly resolution 54/195 (1999).
Intergovernmental organizations are advised that the request for granting of observer status should emanate from a Member State, or Member States, in the form of a letter to the Secretary-General containing a request for the inclusion of an item in the agenda of the General Assembly, in due time for the item to be considered by the Sixth Committee.
Samples for such letters are contained in document A/66/141 (if submitted by 60 days before the opening of the General Assembly session), A/64/193 (20 days) and A/64/232 (thereafter).
For more information, please contact the General Assembly Secretariat.