A tribe north of Auckland has secured kaitiaki visiting rights to three quarries, to ensure the owners are not spoiling the environment.
Ngati Manuhiri has agreements with Rodney Aggregates, Matakana Metals and Millbrook Quarry - all located between Matakana and Pakiri.
Iwi chief executive Mook Hohneck said tribal members were trained to make checks on the health of the ecology.
They focussed on water and wind, which could carry pollutants and harmful particles caused by dust and earth being removed, and rock being blown up, he said.
Ngati Manuhiri had a good relationship with the quarries, Mr Hohneck said.