Among the baptised some are called to the ministerial priesthood as deacons, priests and bishops. Those called to the ministerial priesthood receive the sacrament of Holy Orders, and are consecrated for the service of all the baptised and the building up of the Church. Those who receive Holy Orders live a celibate life and have a special obligation to pray and seek holiness.

A priest presides at the celebration of the Eucharist (Mass) and other sacraments, proclaims the Gospel (Good News), teaches the Catholic Faith and works to build up the local faith community. A diocesan priest works within a particular geographical area called a diocese, usually in a parish, as the co-worker of the local bishop who leads the diocese.

The Archdiocese of Wellington comprises 22 parishes spanning the central New Zealand area from a line between Levin and Masterton in the north to the southern boundary from Kaikoura to Westport. Diocesan priests serve in the 22 parishes and also in schools, hospitals and other social agencies.

Every diocese has a process by which candidates are accepted for the priesthood.