South Waikato iwi Raukawa has refused to give a water-bottling company consent to take water from the Pataruru Blue Springs.
Raukawa say they are kaitiaki of the spring and want to protect it from further commercial use.
The springs supplies 70 percent of New Zealand's bottled water, and Raukawa are worried that letting NZ Pure Blue Springs take more will damage the water quality.
The Waikato Regional Council has advised NZ Pure Blue Springs that for it to consider giving the company a non-notified consent process, it required written approval from Raukawa.
But after talking with their kaumātua and marae in their rohe, Raukawa have declined.
The Raukawa Settlement Trust chairperson Vanessa Eparaima said as kaitiaki they needed to protect their taonga.