The heritage New Zealand category 1 Forrester Gallery was closed in December after toxic mould was discovered in the upstairs gallery, and subsequent inspections found further mould throughout the building and asbestos in some areas.
Fire compliance issues were also identified.
With the gallery closed, planned capital upgrades went ahead and are ongoing. They include the removal of the mould and asbestos-affected kitchen area ($30,000), installing a first-floor kitchenette ($5000), fire-compliant ceilings and doors ($150,000), a new heating, ventilation and air-conditioning system ($100,000) and emergency lighting ($20,000).
From May 21 until yesterday, the Waitaki District Council had dodged questions from the Otago Daily Times about the project's timeframe.
Forrester Gallery, North Otago Museum and Waitaki District Archives director Jane Macknight said the gallery would "hopefully" open in early 2020, not next month as originally planned.
"It's disappointing that we won't be open, but it would be more disappointing to have to come back and do things.
"It's taken significantly longer than we thought but we didn't really have any framework to guide us when we started the project.
"The two big remaining issues are fire rating and getting the climate control worked out. But we are pretty sure we have worked out the top and middle floor, but we want to get it right for the lower floor."
A budget of $575,000 for the project was approved by the council in February and work remained on track to be completed within that figure, Ms Macknight said.
Work includes new flashings for the gallery roofwork, major repair and repointing of the external Oamaru stonework, the updating of all internal wall linings and an upgrade to the drainage systems of the building, which would start soon.
Window frames are also being inspected to make sure they are water-tight, and frescos uncovered inside the gallery will likely be glazed to protect them.
The gallery's collection was being stored on-site in a sealed, temperature-controlled room.
