Since they were first established, the Reformed Churches of New Zealand have sought to develop and maintain relationships with other churches that share similar doctrine and practice.
The mandate to seek and express this unity arises directly from our Lord's high priestly prayer in John 17. When the church of Jesus Christ is divided, whether in doctrine or in practice, she is unable to express the oneness that our Lord prayed for and the love that will show that we are his disciples (John 13:34,35).
But there are sometimes factors which make it either impossible or unwise to merge with other churches, even those of similar doctrine and practice. Geographical distance, language barriers, and even cultural and historical factors, must all be taken into account when relating formally with other churches.
For this reason, our churches use a structure called a sister church relationship. Our churches have adopted a set of rules for sister church relationships. Within this structure, we are able to have meaningful ecumenical contact with a number of churches around the world.
In addition our churches are members of the International Conference of Reformed Churches.