Seems these changes were proposed back in 2008, not sure what stage its at in parliament though.
http://www.nzta.govt.nz/consultation/driver-licensing-amendment-2011/docs/q-and-a.pdf -Removal of the 70km open road speed limit for learner and restricted class 6 holders.
-Making the restricted class 6 test more 'motorcycle specific'
-Removal of the ability to ride a moped on class 1 licence, you will need to get a new 6M moped class and can progress to a class 6 licence.
-Removal of 250cc upper engine limit for restricted and learner class 6.
-Introduction of an upper limit of 660cc and a power to weight ratio of 150kw per tonne. A list of allowed motorcycles will be published in the New Zealand Gazette (and presumably on the internet). Aussie already has this rule in place and here is their list;
http://www.rta.nsw.gov.au/licensing/downloads/lams_list_111205.pdf ~All motorcycle up to 660ml built before December 1960 are approved.
~All motorcycles and scooters with electric powered engines are approved.
~All motorcycles with an engine capacity under 260ml are approved with the exception of:
Suzuki - RGV250
Kawasaki - KR250 (KR-1 and KR1s models)
Honda - NSR250
Yamaha - TZR250
Aprila - RS250
Class 6M didn't proceed but the rest did. 70km/h restriction is already gone, LAM (learner approved motorcycle) is approved and in the pipeline for 2012.
Nice, hope we follow Aussies lead (like we do with everything else)