An iron-sands company has been granted a mining permit to extract iron-sand from the South Taranaki Bight.
The 20-year permit granted to Trans-Tasman Resources (TTR) was the first step in the regulatory process which could allow mining in a 66-square kilometre area of seabed 22 km off the coast of Patea.
TTR wants to suck 50 million tonnes of sand from the seabed each year, take out the iron ore and return about 45 million tonnes of sand back to the bottom.
It wants to do this over 20 years, a total of one billion tonnes of sand.
The mining application was granted after the Ministry of Business, Innovation and Employment assessed the company's technical and financial capability, along with its health and safety and environmental records.
It said that if resource consent was granted, the project would bring considerable benefits.
A decision on resource consent is expected in June.
A critic of the mining on environmental grounds, Kiwis Against Seabed Mining chairperson Phil McCabe said the ecological effects would be massive.
"The life at the bottom of the ocean all the way up through the water column and food web, all the way up to the endangered Maui's dolphin and the blue whale," he said early in April.
He took issue with an assertion by TTR that there would only be small effects on the coastal environment.
"The science we are relying on to make this decision is not providing a level of certainty that makes us feel comfortable."
Hapu along the west coast from Port Waikato in the north to Mokau in the south have opposed the extraction of sand from the seabed.
Angeline Greensill, who co-chairs Nga Hapu o Te Uru, said it was destructive and totally unnecessary.
Her big concern was that if TTR gained a green light for what was currently a fairly small area of ocean, the rest of the west coast will be up for grabs.
"We are really concerned that there are a whole lot of companies lined up to exploit and extract from this zone," she said.