Ryall had requested the report to see whether DHBs had assessed the problems when the "leaky building" issue rose to prominence in the 2000s.
The Ministry of Health told Ryall in the report that it could find no records of a request going to DHBs at the time for assessments but in October 2012 the ministry requested all DHBs provide updates on their buildings.
"It appears that most DHBs did not undertake a specific assessment at the time. For some DHBs this was because their building stock was not of the age or type associated with 'leaky buildings'," the report said.
Counties Manukau DHB was one of those which did carry out an assessment at the time, which is when it found issues with the AMC and Tiaho Mai.
Counties Manukau DHB was yet to inspect the Kidz First children's hospital and the Manukau Heath Park but the ministry report said serious leaky building issues had been identified in 2012 in relation to several buildings.
It was not until August 2017 that the DHB requested $13 million from the Health Minister at the time Jonathan Coleman and Finance Minister Steven Joyce towards the $16m cost to reclad the Scott Building.
It was only when a large piece of cladding fell off the building in April 2012 that the leaking was discovered.
"Further investigation revealed widespread systemic cladding failure with resulting water ingress, timber framing decay and damage," a report from the Ministry of Health said.
There is no reference to the widespread rot or mould that occurred in the years between.
The now $18m reclad of the Scott Building is only just getting started, six years after the issues were reported to the responsible minister and five years after the DHB indicated it was going to remediate the buildings.
Much of that time has been spent in a legal battle with Hawkins, the company that built the Scott Building.
In recent months there has been a furore over the state of the buildings at Middlemore, with rot and mould associated with leaks being discovered in the years since the leaks were reported.
There have also been revelations about sewage leaks, seismic issues and insecure power supply in buildings on the Middlemore and Manukau campuses.
A war of words erupted between Health Minister David Clark and his predecessor Coleman over the issue, with Clark saying Coleman should have been aware of the extent of the problems at the DHB.
Coleman has denied he knew anything other than issues with weathertightness in the Scott Building.
Clark has since been accused of the same thing after the board of Counties Manukau insisted he had been told about the extent of problems with buildings at a meeting in March this year.
He said he was told only of the problems with the Scott Building.