Most locations around the south island would result in red cod and dogfish during the winter months. Still to early for the interesting summer species to show themselves.
Maybe give the Kaikoura wharf a fish at night, use prawn for bait (local supermarket stock it) and hooks around 3/0 in size might result in a few Moki.
If you up near the Marlborough sounds then a drive out to French pass might be worthwhile, the scenery is excellent and if you cast into the pass itself you should get onto Blue Cod.
Have no idea what the fishing is like off the shore in accessible fiordland over the winter months. Could be worth a fish, the same applies for Stewart Island if you get over there. In general winter fishing is slow.
Once up in Tauranga you might get onto the odd Snapper.