In reply to The Peasant:
Hi, with 4-5 days available, it depends on whether you have your own transport? There are loads of places on the South Island to climb rocks or mountains. Assuming you have your own transport you may still be traveling a number of hours, so plan you activities well.
Just a couple of suggestions: For bouldering, Castle Hill is a great area which is about 2.5 hours drive W of Christchurch. For sport climbing Takaka - in Golden Bay area 5+ hours NW drive, Wanaka 5+ hours SW drive, Queens Town 6+ hours SW drive.. Not sure about trad stuff. p.s. Don't quote me on the driving times..
From my nugget of experience, the tramping and mountainous scenery is VERY impressive which is well worth the effort.
See Fiend's great guide to climbing in NZ,
http://www.ukclimbing.com/articles/nz1.html
Hope this helps.