The Foreign Minister is to be investigated over his decision to withhold papers relating to the Malaysian diplomat case.
In late July Murray McCully gave a blanket denial to an Official Information Act request seeking copies of advice and correspondence relating to the use of diplomatic immunity by Malaysian defence attache Muhammad Rizalman bin Ismail.
Ismail had been charged with burglary and assault with intent to rape, but left the country after diplomatic immunity was invoked.
Chief Ombudsman Dame Beverly Wakem has agreed to investigate Mr McCully's decision on an urgent basis.
Labour's foreign affairs spokesman David Shearer said the fact that Dame Beverley was stepping in showed the significance with which Mr McCully's actions were being seen.
"The charges against the diplomat are serious, they involve a New Zealand woman and there is clear public interest in the case both in terms of achieving justice and how this Government handled it," Mr Shearer said.
"Any hiding behind the ongoing investigation by John Whitehead into the matter should be seen for what it is deliberate evasion. The minister releasing documents now will not jeopardise that inquiry. Indeed, it was specifically set up to avoid looking at why Minister McCully himself did not take the matter seriously and why his office did not take it up and ask the right questions," Mr Shearer said.