It also has small field teams, focused mostly on hydrology, stationed in Bream Bay, Lake Tekapo, Rotorua, Napier, Whanganui, Greymouth, Alexandra, and Dunedin.

[3] NIWA was formed as a stand-alone organisation in 1992 as part of a government initiative to restructure the New Zealand science sector.

[4] It was previously part of the Meteorological Service of the Ministry of Transport but was separated into a Crown entity focusing on long-term weather patterns and climate change.

[2] On 26 September 2024, the Minister for Science and Innovation, Judith Collins, announced that NIWA would be acquiring the Met Service.

[10][5] "NIWA's mission is to conduct leading environmental science to enable the sustainable management of natural resources for New Zealand and the planet.

This is a critical part of science in Aotearoa New Zealand as institutes have been criticised for poor representation for Māori and Pasifika researchers.

[14] Past and present staff include: In 2007, 12 NIWA climate scientists – Greg Bodeker, Matt Dunn, Rod Henderson, Darren King, Keith Lassey, Dave Lowe, Brett Mullan, Kath O'Shaughnessy, Guy Penny, James Renwick, Jim Salinger and David Wratt – shared the Nobel Peace Prize with other contributors to the Intergovernmental Panel on Climate Change.

[24] One method of remote sensing measurements at Lauder uses a LIDAR system to generate ozone profiles to 100 km in altitude.

[24] Solar radiation measurements at Lauder are used in studies on the effects of UV radiation on human health and in the solar energy and building industries[29] In 2018 NIWA commissioned 3 powerful Cray supercomputers called Mahuika, Maui and Kupe, forming the HPCF (High Performance Computing Facility).

It also leads investigations such as the analysis of genetic information, the modelling of the impact of climate change and forecasting weather related hazards.

[12] NIWA maintains a range of monitoring networks that collect long-term environmental data, including climate information, sea level, river flows, water quality, and freshwater fish distributions and habitats.

As at 1 August 2008, NIWA had 1339 operational stations in its climate and water monitoring networks, spread throughout New Zealand, including the Chatham Islands.

The National Climate Database, for instance, contains more than 250 million individual measurements (as of August 2008[update]), with records dating back to the 1850s.

NIWA holds the longest continuous record of atmospheric CO2 concentrations in the Southern Hemisphere, measured at Baring Head, near Wellington, since the 1970s.

Along with equivalent measurements from the Northern Hemisphere, taken at Mauna Loa Observatory in Hawaii, these records are used to model the effects of atmospheric CO2 on global climate.

[34] In 2020, NIWA chief executive John Morgan told Parliament the two organizations are like "a car and a truck; both being vehicles but each serving different purposes".

[10] NIWA welcomed the merger announcement, stating that "it will be critical to ensure adequate capability is in place to maintain continuity of weather forecasting services, particularly during this transition..." It also said that it looked forward to legislation facilitating the takeover of MetService.

In a High Court judgement, Justice Geoffrey Venning ruled that the New Zealand Climate Science Education Trust had not been successful in any of the challenges they brought against NIWA.