Palmer argued that the New Zealand government should not be "contracting out" its legal obligations under the OIA by making it subservient to the requirements of a strict confidentiality agreement between the 12 TPP nations.
Justice Collins observed that such a decision "could be consistent" with the act.
Palmer responded: "Our submission is that if there was no other reason for information to be withheld, that agreement cannot provide an additional reason."
Much of the morning's arguments revolved around the fact that neither the minister nor the Ministry of Foreign Affairs had undertaken a full review of the documents in question to determine whether parts that were either in the public domain already or were "anodyne" and uncontroversial could be released.
"The minister failed to undertake a basic element by failing to assess the information itself," said Palmer. "That's the basis of a request for a determination. Blanket refusals are not contemplated by the act."
Palmer also dwelt on the approach being taken by the European Union, which has been willing to allow release of negotiating texts relating to the European-US equivalent of TPP, known as TTIP, and comments by the European Ombudsman suggesting the traditional secrecy surrounding trade negotiations is counter-productive to public trust in such processes.
The hearing is continuing.