The missionary concern of the Presbyterian Church of New Zealand has always been an important aspect of its life. In the matter of missionary work among the Maori people the Presbyterian Church was late in the field, and when it did begin, its activities coincided with a difficult period in Maori-Pakeha relations. The first Presbyterian missionary to the Maoris was the Rev. James Duncan, a minister of the Reformed Church of Scotland. In 1843 he began work in the Manawatu district but, while he laboured faithfully, no results of his work remain in the form of stable Maori congregations. Constructive work began with the appointment of H. J. Fletcher to the Taupo district in 1889, followed by the opening of further work in the Urewera and King Country. In 1905 the Turakina Maori Girls' School was established, the first of a number of schools and hostels which the Presbyterian Church has established for the welfare of the Maori people. Outstanding Presbyterian workers among the Maoris have been the Very Rev. J. G. Laughton and a number of dedicated women. Significant developments in recent years in Maori work have been the constitution in 1952 of the Maori Synod, the establishment at Whakatane of a Maori Theological College, and the extension of work to city areas where large numbers of Maoris are now living.

The New Hebrides was the first overseas mission field of the Presbyterian Church of New Zealand. In 1868 the Rev. William Watt went to the islands as the representative of the Northern Church and in 1869 the Rev. Peter Milne followed as the representative of the Southern Church. The mission has developed into the self-governing Presbyterian Church of the New Hebrides.

The second field was in South China (Canton Villages). The work in this field grew out of the contacts made by the Rev. Alexander Don with Chinese gold diggers in Central Otago. Don's friendly ministrations resulted in the opening of the closed villages of Canton to the Rev. George McNeur, the first of a notable band of missionaries who represented the New Zealand Church in South China for well-nigh half a century until the tides of communism made it necessary for them, in the interests of the Chinese Church, to withdraw. A few of the South China missionaries continued to serve in the British colony of Hong Kong.

The third field was opened in the Punjab, India, in 1909, when Dr W. J. Porteous began medical work in Jagadhri. This mission, which includes evangelistic and educational activities as well as medical, is now part of the United Church of North India.

Further extension of the missionary outreach of the New Zealand Church occurred in 1957 when the General Assembly decided to assist the Church of West Java by providing two missionaries (a minister and a doctor) and in 1959 when a decision was made to cooperate with the London Missionary Society in Papua (New Guinea).