I think Wheeler's idea is that trade with China (#2) is going to suffer because of the Yuan weakening and the turmoil over there due to China's debt so he's weakening his own currency to reflect that. And since the Aussies are #1 on the list, he basically just handed them a swift kick in the butt that's gonna cost the Aussies money on the exchange market for imported goods from New Zealand.
Wheeler just lined his own pockets and basically just dared the Aussies to do something about it. And I firmly believe AU will tank as a result. :-)