The project started in 2000 with a conservation report on the imposing brick and stone church at the northern entrance to Waimate's main street.
The first two stages of the project, costing about $330,000 and paid for, have been completed.
They included bracing and strengthening the church, a new roof, restoration, cleaning and repairing the exterior.
Now the St Patrick's Church Restoration Trust is moving on to the final stage - the restoration and repainting of the interior, with new heating and lighting, expected to cost about $207,000.
Mr Foley said about $70,000 had been raised so far for the final stage, including $7000 from a concert by opera singer Dame Malvina Major attended by about 230 people on November 1.
Painting and reinstating some of the original interior is one of the largest components of the final stage and is expected to cost about $80,000.
Mr Foley said that work was expected to start early next year and would present the church in a glorious condition for its centenary year.
Other items such as new heating and lighting would be carried out as funds were raised, although Mr Foley hoped that could be completed by October, the month 100 years ago when the church opened.
Its centennial celebrations are still being planned, although a day of musical entertainment has been set down for October 25, the closest Sunday to the day the church originally opened.
The work has had to be carried out without the original plans for the church or photographs of its construction.
The trust has been searching for those but so far has only turned up one photograph of the original construction.
That has been published in the Otago Daily Times' "Images from the Past" Saturday column.
