Located in a courtyard behind the present Star and Garter building in Itchen St, the stone stables built in 1861 date from the days of an earlier hotel on the site.
Over the years, the stables have been used at various times as a private residence, a bakehouse and an electrical workshop and store. Its owner, Oamaru Operatic, uses the building for storing props, society president Pat Gunn said.
The state of the roof on the stables had been a concern for some years and, after high winds last year lifted some of the sheets of rusting iron, replacing the roof became a priority.
With the assistance of a builder, a team of volunteers from the society spent several weeks over the summer putting on a new roof.
In the process of removing years of accumulated straw from generations of nesting birds, they were pleasantly surprised to find the kauri timber in the framing was still astonishingly sound.
The work has ensured the retention and preservation of what Mrs Gunn said was "a historically significant building".
