Paradoxically, the court's decision does not mean that the reasons the Minister gave for withholding the documents were necessarily wrong, or that the documents will all now be released.
The decision has already been reviewed by the Office of the Ombudsmen, who considered the contents of the documents covered by the request and agreed with the Minister's decision to withhold them.
As the Chief Ombudsman has already pointed out, that review was concerned with the substance of the documents rather than the process used by the Minister to reach his decision.
So what does all this mean? For a start, it does not mean that the documents will now be released. The Minister will now have to go back and reconsider Professor Kelsey's request for information, using the process set out by the High Court.
He may of course undertake that process and form the view that some of the information he originally withheld should now be released. But he could adopt the same view as the Ombudsman, namely that the information should still be withheld.
In the longer term, it means that people responsible for responding to OIA requests will need to take more care in identifying the documents that have been requested and considering their contents before reaching a decision on whether to release them. This may have unexpected consequences.
Decision-makers under the OIA are entitled to charge for the time taken to collect and review the relevant information, and may decide that the cost of responding to requests will have to increase as a result. This is probably not the outcome Prof Kelsey and the other applicants in the High Court wanted.
Nick Russell is a partner at Chen Palmer, New Zealand public and employment law specialists.