Senior minister Ed Masters said the work on the 151-year-old church would begin in late January and was expected to finish in May.
"It'll be safer, it'll be warmer, and the building will be protected into the future," Rev Masters said.
The future-proofing would cost about $600,000 and the church would be closed for the duration — services and events would be held in the Burns Hall next door.
First Church sat at the heart of Dunedin — the work would make sure it remained so.
"This is about ensuring that we can keep doing that and enhancing it for those things as well."
The renovations were being supported by an $80,000 grant from the Dunedin City Council Heritage Fund, and funding from the Synod of Otago and Southland — additional grants and church funds would
make up the balance, he said.
The church’s switchboard and heating system would be replaced as well as the wiring, the oldest of which had been in use since the 1920s.
A window and the interior lining of the church’s west transept wall, which was made of lath and plaster, would be replaced, and the fire protection system would be upgraded.
