The Auckland company planning to build a water-bottling plant at Poroti Springs near Whangarei has had its property damaged in a graffiti attack.
Zodiac Holdings and its subsidiary New Zealand Spring Water, have consent to take water from the aquifer feeding the springs.
It recently gained consent to double the size of its planned factory despite the objections of local Maori.
Zodiac's signs and a building on the site are now covered in slogans and obscenities.
The Whatitiri Maori Trustees who own the springs warned this week that hapu resentment over the project was close to a tipping point.
A spokesperson, Meryl Carter, said they had argued their water claim in every forum but they've lost each time and the people see that lawful action has got them nowhere.