Historically in New Zealand, heights have been defined in terms of 13 local vertical datums referenced to local mean sea level (MSL).

The 13 local vertical  datums were established by determining mean sea level at a tide-gauge and then transferring this level to benchmarks in a network. The majority of observations in these long and often poorly constrained networks, were made using precise levelling.

To account for changes in the Earth's gravity field an approximate orthometric correction was applied to the levelling observations to give normal-orthometric heights in relation to the tide-gauge MSL.

Sea level is known to vary around the coast of New Zealand. This means that the level of MSL determined each datum's tide-gauge will be different and that heights measured between adjacent datums will not agree. It is therefore important that the vertical datum of a height is checked before it is used.

In most cases the level of MSL for the vertical datums was determined prior to 1960 and has not been updated since then, even though MSL has changed by unknown but measureable amount.

Read about tidal level information for surveyors about relating the local datums to mean high water springs (MHWS).

Heights in terms of the local datums can be related to the NZVD2016 or NZGD2000 by using the NZGeoid2016 geoid model and the appropriate Vertical Datum Relationship Grid. The conversion of heights between the different datums is described on the height conversion pages.

Mean sea level vertical datum locations
Mean sea level vertical datum locations

NZVD2016 heights are also published on the Geodetic Database for all geodetic marks included in the National Geodetic Adjustment. The table below compares the height of the reference mark for each local vertical datum with the NZVD2016 height as computed using the relationship grid, and as published from the National Geodetic Adjustment. 


Datum Code

Reference Mark

Reference mark height in terms of local datum (metres)

Reference mark height in terms of NZVD2016 (metres)

Determined by relationship grid (HA+OA)

Reference mark height in terms of NZVD2016 (metres)

From National Geodetic Adjustment 9-11-2016

One Tree Point 1964ONTPHT1964RNZN BM (DJM9)3.143.055


Auckland 1946AUCKHT194698-21 SO 69501 (DD1N)3.4913.124


Moturiki 1953MOTUHT1953BC 84 (B309)3.1412.942


Gisborne 1926GISBHT1926GB 01 (ACVP)3.0392.701


Napier 1962NAPIHT1962H 40 (B3XM)3.913.717


Taranaki 1970TARAHT1970New Plymouth Fundamental (AGMH)4.9064.6084.609
Wellington 1953WELLHT1953K 80/1 (ABPB)2.0871.699


Nelson 1955NELSHT1955N 1 (AC4T)3.5323.203


Lyttelton 1937LYTTHT1937UD 40 (B40V)3.267



Dunedin 1958DUNEHT1958WW 83 (AFEQ)2.7372.360


Dunedin-Bluff 1960DUBLHT1960Z 41 (B3R8)112.699112.381


Bluff 1955BLUFHT1955Bluff Fundamental (ABCC)7.0116.697


Stewart Island 1977STISHT1977N (Paterson SD) (A017)44.143.8n/a
Last Updated: 8 June 2017