Health Minister Tony Ryall threatened to use special legal powers to force hospital bosses to do his bidding if they did not support a project to save $700 million.
The threat came after flaws in the plan were exposed in a high-level review which questioned where the savings had come from.
An Ernst & Young review into the plan found the savings were based on assumptions which were "out of date" and "the basis on which they have been calculated are not clear".
The money is being saved by merging back-office functions of district health boards to get better deals with fewer staff. It happens through a Crown-owned company called Health Benefits Ltd (HBL).
Documents released through the Official Information Act show the path has been rocky, with a communication breakdown between the boards and HBL.