Built in 1872, the New Zealand Historic Places Trust category 1 classified church is one of Waimate's most important historic buildings.
"It is of exceptional heritage value to the town and district. It is one of the most iconic buildings in Waimate," restoration project committee chairman Paul Studholme said.
The church plans to officially launch its restoration project at a function in its Parish Centre on March 2.
Mr Studholme said the project would be a challenge, but he was confident the community would support it.
Construction of the church, designed with input from architect Benjamin W.
Mountfort, started in August 1872.
It was consecrated on May 4, 1873.
During its life, changes have been made including the addition of the lychgate in 1902 and the bell tower in 1903.
In 1923, the chancel and sanctuary were replaced, the new addition incorporating two windows made by Morris and Co, England.
In 1963, a lady chapel was added.
The most significant change occurred in 1999, when a new lounge and meeting rooms, designed by Sir Miles Warren, were added.
However, Mr Studholme said the fabric of the church had weathered over the years.
"The church is now 136 years old. The elements have taken their toll and there is urgent need for restoration," Mr Studholme said.
A considerable amount of exterior work was needed to bring the church back its original condition, including replacing decayed and damaged framing, cladding and other parts, repainting exterior timber, replacing the leaking shingle roof and other repairs.
The interior required renovation, upgrading and restoration including a fire detection system, upgraded heating, replacement of wiring, updated lighting and sound system.
The bell tower and lychgate also needed repairs and restoration.
Consultation with conservation architect Guy Williams, a quantity surveyor, trades people and St Augustine's vestry confirmed a likely cost for the project of $485,000.
That would result in a restoration that would ensure the buildings lasted for another 100 years and more, an investment needed for the town's future generations, Mr Studholme said.
