Heavy Motor Vehicle : A motor vehicle that is either: (a) of Class MD3, MD4, ME, NB, NC, TC or TD; or (b) a vehicle (not of a class specified in Table A: Vehicle classes) with a gross vehicle mass that exceeds 3500 kg.
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}