In 1964 New Zealand began helping Malaysia to fight Indonesia's attempt to wrestle control of the North Borneo territories in what was known as the Confrontation Campaign. This role, which continued until 1966, saw New Zealand soldiers mount covert cross-border raids into Indonesia.
On 11 August 1966 representatives of Indonesia and Malaysia signed a peace treaty in Bangkok. Hostilities were officially at an end. 1RNZIR completed its withdrawal from Borneo in October the same year.