Kupu whakataki / Introduction

The Manukau Harbour is a large, productive, and important body of water for both Tāmaki Makaurau and Aotearoa. The harbour and surrounding catchment contain a diverse range of habitats that support a wide variety of plants and animals. The coastline, catchment, and harbour are also important to people. These areas are of great spiritual and cultural value to mana whenua and hold a mauri that binds people to the land and sea. They are places to live, places to work, and provide space and opportunity for recreation.

The Manukau Harbour is the second largest estuary in Aotearoa (with a surface area of ~370 km²) and drains a comparatively small catchment (~920 km²). The dominant land use varies considerably around the harbour, with indigenous forest and scrub/shrubland to the north (part of the Waitākere Ranges), urban areas (including industry) to the east, and exotic grassland and cropland to the south (including the Āwhitu Peninsula).

Auckland Council carries out long-term State of the Environment monitoring across the region, including in and around the Manukau Harbour. Monitoring in the Manukau began in 1969, with several programmes now spanning several decades. In 2021, A Synthesis of State of the Environment Monitoring in the Manukau Harbour provided a comprehensive overview of the harbour, including its ecological values, monitoring programmes, and catchment initiatives.

Following this, Auckland Council has been developing a strategy to achieve better environmental outcomes for the Manukau Harbour. The strategy provides an overarching framework and clear direction intended to support Auckland Council and Council-Controlled Organisations to prioritise, coordinate and align investment and activities over time to achieve these outcomes.

As part of this strategic work the Manukau Harbour Environmental Assessment, published in 2025, provides an evaluation of drivers, pressures, state, impacts, and responses relating to the environmental health of the harbour, drawing together findings from the 2021 synthesis report.

In September 2025 Auckland Council published the five-yearly regional State of the Environment report which brought together results from technical reports, covering the state and changes over time in air, land and water domains, to tell the story of the health of our natural environment across Tāmaki Makaurau.

In this report we provide an update to the monitoring presented in the first Manukau Harbour synthesis report, using the latest regional monitoring data to assess the current state of the harbour and its catchment. It supports the development of a Manukau Harbour Strategy and will inform an update to the Manukau Harbour Environmental Assessment.

Auckland Council, July 2026

See also

The health of Tāmaki Makaurau / Auckland’s natural environment in 2025

A synthesis of state of the environment monitoring in the Manukau Harbour, June 2021

Visit our Environmental Data Portal for more information and updates.