Thats fine, and its about time they have started doing that. But the harbour doesn't flush well enough due to all the rivers feeding into the harbour. If you look over google maps and count how many rivers feed the harbour you will see why everyone chooses Taka boat ramp. Taka is tried and true, not to mention its far closer to open sea then the harbour is. The further away from harbours and rivers you get the better the water quality gets which is what we want for reef aquriums.
Best way to check the water quality would be to use every Hanna meter you can think of, and compare the results.
I don't think many NSW using Auckland reefers would risk hundreds to thousands of dollars of livestock, because they think the harbour is safe to use.