A building at Middlemore Hospital is being flagged "earthquake prone".
An independent report showed that the hospital's Galbraith building's is unstable and its future uncertain.
Board chair Vui Mark Gosche said the Galbraith building was over 50 years old and in that time, although the quality of the building has not changed, building standards have.
He said results of a detailed expert seismic assessment, which has been peer reviewed, showed that the building was 20 per cent of New Building Standard (NBS).
"The building's rating is also affected because of the importance of the role that the building would be expected to perform post-disaster."
To bring the building up to scratch to the standards, Gosche said it will cost more than $74 million.
"That's excluding costs of fixing or relocating critical building services infrastructure such as power, medical gas, data.
The Galbraith building currently houses a birthing unit, two maternity wards, early pregnancy assessment clinic, gynaecology care unit, ophthalmology clinics, plastic surgery, clinical engineering, infusion centre, blood bank, radiology and executive offices.
"Strengthening work would involve major relocation for clinical services located on levels two to five, notably the two-year relocation for maternity wards, and Assessment Labour and Birthing Unit," Gosche said.
Gosche said that because of the age of the Galbraith building, there were also some issues with asbestos building materials.
"However there is no need for alarm as appropriate monitoring and control are in place to ensure the safety of staff, patients and visitors.
"Many public buildings, including schools and hospitals, built between the 1940s and 1980s have been built using products containing asbestos.
"Intact and undisturbed asbestos material generally does not pose a health risk and, in the case of Galbraith, a programme of asbestos remediation is underway, including asbestos removal and repair work, air monitoring and control," Gosche said.
He said the Board has now asked management to provide more detail on the options moving forward.
"One option which includes strengthening the exits to the building and a 'nil strengthening' option, before the Board makes any decision about the future of the Galbraith building. Staff, patient and visitor safety is obviously a priority for the Board."
Gosche said Auckland is an area of low earthquake risk when compared to Wellington, Christchurch and even Hamilton.
"The earthquake risk of an area affects the timeframes building owners have to complete building strengthening work or demolition.
He said in high-risk areas like Wellington, owners of priority building, like hospitals, that are earthquake prone have 7.5 years to strengthen or demolish. That's compared to the same buildings in Auckland which have 35 years and are not classed as priority buildings.
Auckland Council has been notified of the final results of the seismic assessment of the Galbraith building.
Information about the Galbraith building will be made available to staff, patients and visitors, including at the entrance to the building.
