I know this is a very old post but I have the same problem. I’ve been fishing the area landbased for months now and caught nothing but butterfish and had one huge strike on a whole crab bait but didn’t hook up. It is some of the most fishy looking coast I’ve ever seen but so far it is some of the worst fishing I’ve ever had in my life.
There are awesome ledges everywhere but they are always under cliffs, very high cliffs, and totally inaccessable. There are also very few access roads to the miles and miles of rock ledges. Almost the whole Catlins coast is rock ledges. Bull kelp is everywhere too but probably the biggest problem is the sheer amount of seals, sealions and penguins. Almost every decent ledge is covered in seals and seals live on fish. The fish in the area must get an absolute hammering.
Having said that… everywhere you go in the Catlins you hear rumours of locals catching limit bags of Blue Cod off the rocks but the locals are very secretive about locations. I have yet to catch a single blue cod despite using ridiculous amounts of berley.
I still think the Catlins is going to turn out to be one of the top rockfishing spots in the country once somebody puts in the time and effort to suss it out. From my own experience I’m still looking for a proper deep water ledge. So far all the ledges I’ve fished have been way too shallow for my liking. I’ve seen very deepwater ledges from the top of cliffs but couldn’t get down to them. I haven’t given up yet though.