The links below access tide tables for the current year for a location near the wharf. The times of high and low tide will be a few minutes earlier for the harbour entrance. For the height datum, you have the choice of either: mean sea level - MSL; or chart datum - CD.
It's entirely up to you which datum you choose. Personally, we find MSL more useful because for example for mussel gathering we can tell at a glance if the low tide will be a low one (more mussels exposed) or a high one (we're gonna get wet).
For the time datum, you have a choice of NZ Standard Time - NZST - or NZ Daylight Saving Time - NZDT. NZDT only applies from the 3rd Sunday in September until the 1st Sunday in April, so the NZDT tables have only those months. For the remainder of the year, you will need to use the NZST tide tables.
From Dec-2012, we are pleased to offer a new service. You can find out the tides anytime (past, present or future) by going to: Daily Tides. This service is running on a tiny computer called a Raspberry Pi. There are some details about it here.