If you're going to focus on bait fishing, there are quite a few rods which will handle catching fish right from cod up to kingies.
A significant factor is how robust you want the rod to be.
Many modern rods are made from graphite, or a composite of graphite and fibreglass. Graphite is light and powerful, but fragile. Glass is much more forgiving of being bent at funny angles, left in rod holders etc, but is heavier.
Another question is what weight line you want to use, and if you want to use monofilament (nylon) or braid.
And as Stripstrike says, overhead or spin set up? The deeper the water, the more you probably want to think about overhead.
Relatively inexpensive options to consider would be (all come in spin or overhead formats):
1. the Daiwa VIP870 - one of the all time classics, nice and flexible in the tip, but plenty of grunt as well. Fibreglass. Has good Fuji components.
2. any of the Ugly Stiks in the 8-10kg line rating. Similar rods to the VIP, glass with a graphite core. Almost unbreakable. Good Fuji components. The Black Tiger is a popular model.
3. An Okuma X Factor in the 10kg class - a composite, so a bit lighter than the first two mentioned, but a bit more fragile.
Particularly the first two rods I've mentioned, combined with a quality reel, should last a long time if you look after them well - in terms of cleaning, not attaching hooks to rod guides, spraying with Inox after use etc.
Somewhere like Hunting and Fishing in the Nelson/Picton/Blenheim area should be able to sort you out with a good boat rod combo suited to the Sounds. you're probably looking at $350 min for a quality combo.
If you want to do kingfish jigging, which tests rods and reels and anglers to the limit, then you really need specialist gear. There are some absolute horse kingies in the Sounds, from what I've seen on ITM Fishing Show etc. Short graphite rods, and reels with massive drag capability. That gear isn't cheap.