Seriously though...
Personally I do not know of any star parties, but there will no doubt be dark sky viewing in Chch or Dunedin at their respective observatories.
West Melton in Chch is a pretty good site. Check out CAS at
http://www.phys.canterbury.ac.nz/cas/ E-mail them directly should help.
Good luck, and enjoy the southern vistas.
The Auckland society has a star party in September (7-9th) at Waharau if your going to be up this way. Check it out
http://www.astronomy.org.nz/aas/pub/waharau.asp
Cheers