"Lack of funding to achieve planned demolition or replacement has meant that services have remained operational in these buildings – the average age of CM Health's clinical buildings on the Middlemore Hospital site is 40 years," the reports said.
Between 2008 and 2012, the "funding signals for the health system, and consequently CM Health, significantly shifted", the reports said.
The 2008 global financial crisis and Canterbury earthquakes had significantly constrained Crown capital availability.
"In addition, CM Health experienced reduced annual operating revenue growth that impacted on forecast investment affordability.
"CM Health has made trade-offs by limiting investment at strategic, tactical and operational levels to balance demand risks. The trade-off has been an underinvestment in a portfolio of (ageing) buildings in an environment of legislation amendments resulting in higher statutory non-compliance risks. Some clinical buildings are potentially unsuitable for immediate service expansion or deteriorating at a rate faster than their original anticipated useful life."
The DHB had reached "tipping point" where demand from population growth had overwhelmed the existing infrastructure and investment could no longer be delayed.
It warned that it required urgent investment to expand services to cope with an expected winter influx of patients. "We have, or are at high risk, of exceeding CM Health's capacity for the quality and safe delivery of essential health services."
The reports said the DHB had no "complete and consolidated view" of its investment-critical assets. It had small pockets of information and asset condition information was about 10 years old.
"It is suspected that a large number of CM Health's critical assets are at high risk of failure i.e. they have failed in the past, their condition has deteriorated to the point they are likely to fail, or they are dependent on a surrounding environment/structure that is in poor condition.
"CM Health cannot maintain its facilities, clinical equipment and ICT from an annual depreciation, capital and operating budget. The accumulation of facilities maintenance is evidence of a trade-off that is not sustainable. CM Health has 'sweated' a number of its assets to the point of failure."
Among issues outlined in the reports are:
• Passive fire protection at the Manukau SuperClinic had been incorrectly constructed. "This was not immediately identified at the time of the construction as an independent fire engineer had formally signed off the installation."
The issue had been fixed at the SuperClinic, but other buildings suspected to have the same issue had not yet been inspected, including Kidz First children's hospital and the McIndoe and Scott buildings.
• Continued lift failures at Middlemore and Manukau: between January 2015 and September 2017 more than 1200 lift breakdowns were reported.
• At Manukau SuperClinic there was a history of multiple and prolonged power cuts, cladding issues, regular failures of the sterile equipment supply and the presence of asbestos.
DHB acting chief executive Gloria Johnson, in a letter accompanying the reports, said the reports were submitted in December to the Ministry of Health's national Capital Investment Committee (CIC), which approved the strategic assessments regarding urgent investment in hospital service capacity and fixing its critical buildings.
Health Minister David Clark said it was common knowledge that health had been underfunded in recent years.
"Unfortunately DHBs, including Counties Manukau DHB, have found themselves having to choose between funding services for patients and investing in the proper maintenance and upkeep of facilities," he said in a statement.
"Fixing the backlog of building issues in Health will take time. Next week's Budget will begin laying the foundations for a stronger public health service, with modern facilities, which is there when people need it."
Comment was also being sought from new board chairman Mark Gosche and Gloria Johnson.
The Government recently signed off on an additional $11.5 million to repair Middlemore's Scott Building, one of the worst-affected, taking the total for the project to $27.5m.
The DHB's Strategic Assessment Case written in November sets out $123m worth of work needed across multiple buildings, although that figure is now regarded as an underestimate.