This wooden Gothic Revival church was designed by the prominent Christchurch architect Benjamin Mountfort and completed in 1897.

In 1982, St Mary's Church was moved across Parnell Road to its present site beside the Holy Trinity Cathedral.

Mountfort seems to have ignored the perishable and limited qualities of wood, and built a vast church worthy of the finest stone.

St Mary's covers an area of 840.0 square metres (9,042 sq ft) and has architectural features normally associated only with the great medieval cathedrals of Europe.

In an area where snow does not occur, this gives the façade, with its protruding decorated architrave above the first clerestory, an almost 'whimsical Swiss chalet atmosphere', which adds greatly to the building's distinctness.

St Mary's Cathedral Church was registered by the New Zealand Historic Places Trust as a Category I building on 26 November 1981 with registration number 21.