Looks like the Habour entry to me. If so there is a tide current of around 4-7 knots. Tides range from 3 to 4.5 meters. I used to cross the Manukau Bar in my boat and that was real scary.(Same coast) Could only do it on a high or low tide with the swell less than a meter.
If you try to surf these spots your a goner. Lots of Sharks and very strong currents. Head for Ahipara (Shipwreck bay) in a 4-5 meter SW swell and you will get one of the longest left handers you can imagine. Very fickle however.

Deano