The Māori owners of Porotī Springs near Whangarei say they are not responsible for a protest banner at the site and will not be taking it down.
A large sign has gone up at Porotī telling councils and an Auckland developer to keep their hands off the resource.
Zodiac Holdings recently gained resource consents for a water-bottling plant across the road from the springs reserve owned by the Whatitiri Māori Trustees.
The owners say they did not put the sign up.
However Trustees chair Meryl Carter said there was deep unease in the hapū over the plan and they were entitled to express it.
Ms Carter said Porotī trustees were worried about the impact on the springs when the factory tapped into the aquifers that feed them and also concerned wastewater from the site could pollute springs.
The trustees hope to challenge the resource consents.