This has been brought up by the process around ACTA / TPP and other free trade negotiations. Such negotiations often happen in secret, and the results can be presented to parliament almost as a fait-accompli. Entering into treaties is one of the remaining Royal Prerogative powers and is regulated by a process under Standing Orders rather than through legislation. (See http://www.mfat.govt.nz/Treaties-and-International-Law/03-Treaty-making-process/index.php).
I'd suggest the following improvements:
- NZ negotiators may not take part in treaty negotiations unless there is agreement for minutes to be published within 30 days of any meeting.
(The exception being where the negotiations concern a current or imminent conflict and the Minister certifies that secrecy is essential to the prospects of coming to an accord. I'm thinking here of something like the East Timor situation).
- The parliamentary process to approve a treaty should be akin to passing a bill.
- A treaty must be reported on by the A-G as to whether it conflicts with BORA. If so, the treaty can only be ratified after a referendum with a supermajority.
- A treaty must be reported on by the A-G as to whether it conflicts with the Treaty of Waitangi. If so, the treaty can only be ratified after a referendum returns a majority amongst both Maori and general electorates.
- A treaty provision which contravenes either BORA or the Treaty of Waitangi (and which has not been approved through referenda as above) can be voided by the courts.