Requirement to issue reasoned decision

NewZealand Electoral Act 1993 (2010), Part 8 –Election petitions

242 Decision ofcourt to be final

All decisionsof the High Court under this Part shall be final

and conclusiveand without appeal, and shall not be questioned in any way. Decisions by thefirst instance bodies can be appealed to the High Court. 

http://aceproject.org/ero-en/regions/pacific/NZ/new-zealand-electoral-act-2010/view