The company granted permission to operate New Zealand's first tidal electricity station, in Kaipara Harbour, says the machinery will be pulled from the water if it causes any damage to the environment.
Conservation Minister Kate Wilkinson has approved the staged installation of 200 tide-driven turbines, despite serious concerns the project will kill Maui dolphins and affect fishing stocks.
The Kaipara is the nursery for virtually all North Island snapper.
Crest Energy chair John Maclachlan says the turbines could actually act as a reef, attracting fish stocks to the area.
He also says measures have been put in place to protect the Kaipara.
"The minister has very wisely, as part of the consent, made the ruling that if there any negative effects then the whole project has to be abandoned, the thing's removed and the Kaipara's returned to exactly the same state it is in now."
