The extent of the leaky and rotting buildings at Middlemore Hospital was not revealed to the current or former Health Ministers.
Health Minister David Clark said he had some frank words to the Counties Manukau District Health Board who only told him about one of the four buildings with critical problems.
The mouldy and leaky hospital buildings house elderly people, children with breathing difficulties and a neonatal unit.
But the DHB has said patient safety is not compromised as long as the fungal spores stay in the walls.
Despite the DHB knowing about the leaks and mould since 2012, it has defended its decision not to tell some of its staff, including nurses.
A spokesperson has said it wanted to wait to secure extra funding needed to rebuild one of the buildings before telling staff.
That funding, an extra $11.5m, was announced yesterday by the government.
However, during a briefing last week with the Health Minister, the DHB did not tell David Clark about the three other buildings that were also leaking and mouldy.
Dr Clark was not happy about that and wanted an explanation.
"I'm disappointed the other issues weren't raised with me during that meeting. I am expecting now the DHB to outline to me their plan for managing these issues," he said.
"This is something DHBs should be managing and something they should have a plan for."
The previous government did not make fixing the buildings a priority, Mr Clark said.
However, former health minister and departing National MP Jonathan Coleman said he was not briefed on the problem.
"The bottom line is, David Clark is part of a government who have promised another $8 billion into health, so now is their chance to walk the talk," he said.
Dr Coleman was also asked whether it was fair for the Labour government to blame National.
"Well, the reality is the money has to be spent at some stage and the Labour government have promised to inject more money so this is their big chance to go ahead and do it," he said.