A mining company has applied to mine iron sands off the coast of South Taranaki, sparking fears for the quality of the local marine environment.
The application by Trans-Tasman Resources involves 65.76 sq km of seabed up to 36km west of Patea.
The mining company hopes to extract up to 50 million tonnes of sand per year, which would be processed aboard a specialised ship.
It says the project would pump more than $300 million into the national economy and provide 250 new jobs.
The company also says it has spent millions of dollars to mitigate the environmental impact and is confident any effects, such as sediment plume in the water, will be short-lived.
But the group Kiwis Against Seabed Mining says the company plans to siphon up a massive amount of sand which will adversely affect the area's delicate eco-system.
Spokesperson Phil McCabe says the volumes involved will smother the local reef systems and choke the phyto-plankton which is the cornerstone of the area's marine life.
"There's really strong opposition from surfing communities, fishing communities, and all the small communities up and down the coast. It's a practice that will degrade the marine environment."
Mr McCabe says the group has walked, cycled, and kayaked from Wanganui to Piha and found residents all along the North Island's west coast are opposed to it.
The application is subject to new rules, enacted this year, which require environmental issues as well as economic benefits to be considered before consents are granted for industrial activity within New Zealand's Exclusive Economic Zone.
Public consultation on the application will begin when the project is formally notified.