Officials privately warned the Government that backing the United Nations Declaration on Indigenous Peoples could influence domestic courts' interpretation of New Zealand law.
A Ministry of Foreign Affairs report released to the Herald under the Official Information Act reveals that officials were also concerned the declaration could come to be regarded as customary international law and binding on countries even though the document did not have the binding status of an international treaty. The warnings are likely to be seized upon by Act whose leader, Rodney Hide, has previously slammed National's decision to support the declaration on the basis it would have no practical effect as "naive in the extreme".
The ministry's report also said that supporting the declaration could raise expectations among Maori in "significant new policy areas and in more general policy engagement with Maori".
Ministers were also told articles in the declaration could be interpreted as implying a right of veto for Maori over democratic and legislative action.
"This would have major implications for New Zealand's constitutional arrangements and for the implementation of domestic laws like the Resource Management Act."
Despite that National ministers, who had been lobbied intensively by the Maori Party to support the declaration, decided New Zealand should reverse its previous opposition to the declaration. However, that backing also came with an attached statement expressing support on the provision the declaration operated within the confines of New Zealand's "unique constitutional, legal and policy frameworks".
The Cabinet also took the precaution of ensuring that statement was read to Parliament - a move which would enable it to be admitted in court as evidence under the Evidence Act. Ministers expected the Government's proviso would be taken into account by courts and tribunals when determining the Crown's legal obligations in areas addressed by the declaration.
Some of the officials' advice may have been even stronger.
Much of the legal advice in the reports released to the Herald under the Official Information Act was blacked out on the grounds of being legally privileged information.