An application to mine South Taranaki's ironsand - worth an estimated $1.1 billion a year to the value of goods and services produced in New Zealand - has been granted consent.

Trans-Tasman Resources applied to extract 50 million tonnes of material from the seabed off Patea and export 5 million tonnes of iron sand every year for 35 years.

The proposal to mine ironsand from 66 square kilometres of seabed offshore from Patea received 13,733 submissions, most opposed to granting consent.

The application was considered by the Environmental Protection Authority (EPA), which held hearings in Wellington and Taranaki and deilvered a majority decision today.

Kiwis Against Seabed Mining (KASM) and Greenpeace, opposed the application, have objected to this requirement for more information - supported by local tribe Ngati Ruanui and Forest and Bird.

The Ministry for Business, Innovation and Employment supported the application, saying New Zealand has been mining ironsand since the 1960s.

The west coast of the North Island has some of the largest ironsand deposits in the world, stretching 480km from Kaipara to Whanganui.

The ministry managed New Zealand's petroleum and minerals, with an aim to have them exploited as quickly, efficiently and sustainably as possible, by companies with high environmental and health and safety standards.

Giving consent to TTR would add wealth to the country, encourage overseas investment and further the Government's growth agenda, the ministry submission said.

With iron ore valued at US$40 million to US$50 million a tonne, the Government would get an extra $7 million in royalties each year, doubling its total from mining.

The worth of annual exports would increase by $312 million to $350 million.