Te Tai Tokerau independent MP Hone Harawira says an experimental tidal power plant to be built in the Kaipara Harbour is a threat to fish supplies.
Conservation Minister Kate Wilkinson last week approved Crest Energy's plan to build the first three of 200 turbines planned near the harbour entrance.
Mr Harawira told Waatea News the minister has failed to listen to iwi and local arguments against the plan.
He likens the project to dumping a "mountain load of cars" in the middle of the harbour.
Mr Harawira says the plant will wipe out what is the biggest snapper nursery in the county.