Offshore mining could make a large leap forward this week as New Zealand is set to decide if it will approve Trans Tasman Resources’ plans for an underwater iron-ore operation.

If approved, it would likely become the world's first commercial metals mine at the bottom of the sea.

"A lot of people are watching the Trans Tasman Resources outcome," said Michael Johnston, chief executive of Nautilus Minerals, which is working on a deep-sea project off Papua New Guinea and is also in talks with New Zealand told Reuters.

Other countries in the Pacific looking at underwater mining include Fiji, Solomon Islands, Tonga and Vanuatu, which have all issued exploration licenses. Cook Islands in the South Pacific plans to put seabed exploration licenses up for bids later this year.

In the 750,000 sq km (290,000 square miles) of territorial waters around the Cook Islands are mineral nodules the size of potatoes to lettuce heads and rich in manganese and cobalt, a resource Imperial College marine geoscientist David Cronan estimates at 10 billion tons.

"If only 10 percent of that resource can be recovered it will be one of the largest mineral deposits ever discovered. It is a world class mineral deposit," says the Cook Islands National Seabed Minerals Policy, approved on June 10.

The push to explore the ocean is gaining momentum as ore grades on land decline and demand grows for metals in high-tech applications, and is more feasible now with the help of technology developed for the deepwater oil and gas industry.

Still, there are technological hurdles and fears among scientists and environmentalists that mining could destroy fragile fisheries and exotic creatures at the bottom of the ocean.

"Deep sea mining is coming faster than the scientific community can monitor it," said Carlos Duarte, director of the University of Western Australia's Oceans Institute.

Trans Tasman Resources, which hopes to start mining in 2016, already has a mining license but needs a marine consent from New Zealand's Environmental Protection Agency (EPA).

This is the EPA's first test of regulating mining in the country's territorial waters. Its next is an application from Chatham Rock Phosphate, seeking to mine phosphate several hundred kilometers off the east coast of the South Island.

Others waiting in the wings include Neptune Minerals, with deep sea tenements covering 175,000 sq km off several South Pacific countries, including New Zealand.

While the world's biggest miners have no deep sea mining tenements, Anglo American PLC is keeping an eye on underwater prospects with a 5.95 percent stake in Nautilus.

The biggest backers for Nautilus are Omani oilfield services billionaire Mohammed Al Barwani and Russia's richest tycoon Alisher Usmanov's Metalloinvest Holding, who together own 40 percent.

The Canadian company aims to dig up a seafloor massive sulfide deposit, Solwara 1, about 1,600 meters underwater off Papua New Guinea, starting from 2017.