This series contains annual reports of the Secretary-General of SEATO (South East Asia Treaty Organisation). These records are the copies received by the Department of Defence SEATO sub-registry in Australia. In addition, copies of SEATO Documents controlled by the Department of Foreign Affairs and Trade from A4311, 'Cumpston Collection' of documents relating to the history of Australian foreign policy, have been combined with the Defence SEATO holdings to form this and related series.

The SEATO Council of Ministers decided at its third meeting in March 1957 to appoint a Secretary-General and Deputy Secretary-General who took office in September. The Secretary-General was responsible to the Council Representatives for the overall administration of the civil organisation, attending all Council meetings and acting as spokes-person.

The Secretariat to the Secretary-General was responsible for maintaining the SEATO central registry, which issued, controlled and listed all the records produced by SEATO using an alpha-numeric system modelled on those of other international organisations. Each member country was expected to maintain a separate SEATO registry which received copies of documents distributed from the Secretariat's registry. The Department of Defence provided Australia's main registry in Bangkok and established sub-registries in both Bangkok and Australia.

The reports of the Secretary-General to the Council held in this series were produced annually. They have been allocated a year infix with an 'SG' [Secretary-General] prefix and 'Rep-C' [Classified Report] suffix. They are held in booklets with blue bindings.

The system of arrangement imposed on these records once received by the Department of Defence sub-registry in Australia has not been established. The records in this series have consequently been arranged to reflect the annual sequence employed by the Secretariat's central SEATO registry.

No evidence has been found of control records used by the Australian SEATO registry or sub-registries. Series A9948, Booklets entitled 'SEATO Document Lists', chronological series, while prepared retrospectively by the SEATO Secretariat, can be used to identify individual items under the current system of arrangement.

The consignment list for this series is composed of the entries for the reports of the Secretary-General in the SEATO document lists. The entries have been annotated to show where reports are no longer extant or are held in the consignment.