The Southern District Health Board says it faces a major challenge keeping a Dunedin hospital building running until its replacement is built.
A recent report found the 47-year old Clinical Services Building needs $50 million of work to keep operating for a decade.
The DHB has just spent $1.2 million to seal every window and concrete panel to stop water dripping from light fittings and into operating theatre corridors.
Its facilities manager, Warren Taylor, said the building's pumps and other infrastructure are also increasingly failing as the building reaches the end of its economic life.
Mr Taylor said planning for the hospital's total refurbishment was only at a preliminary stage, so the DHB will have to keep the building going for up to 10 more years.
The DHB's medical director, Dick Bunton, said patient care was still good, but it was getting harder to provide.
Mr Bunton said the building, which was opened in 1967, was no longer fit to house all Dunedin hospital's operating theatres, laboratories and emergency department.
It is not only wearing out, it is seriously over-crowded.
The theatre corridors are lined with equipment needed for 10,000 operations a year because there is nowhere else to put it.
The problems are most evident in the Intensive Care Unit, which three months ago lost the right to train doctors into intensive care specialists because of the cramped physical environment.