The southern Great South Basin is included as one of 25 offshore and onshore oil and gas blocks being put out to tender for exploration, under five-year permits.
The new policy of Government permitting agency Petroleum and Minerals New Zealand replaces an earlier scheme of "priority in time" applications, a first-in first-served process where companies could apply for any area around the country.
"Using an annual block offer approach enables the Government to take more proactive control over where and when areas are opened for exploration. It will also provide more certainty and opportunity for upfront engagement with iwi, local government and industry," the agency said.
The blocks offer by tender will now be the exclusive application format, but has been used in the past, including a Great South Basin tender in 2007, touted at the time as potentially attracting up to $1.2 billion in exploration spending.
In mid-2007 oil giants Exxon and OMV were separately awarded permits in the Great South Basin but Exxon pulled out in October 2010, then in August last year OMV and Shell announced a partnership to continue Great South Basin exploration - valued at about $50 million.
At present the seismic vessel Polarcus Alima is at sea in the Great South Basin, contracting in behalf of OMV and Shell.
Between last November and July, the Polarcus wants to acquire a minimum of data covering 2250sq km, but is targeting a total 4000sq km, of first-time 3-D surveying, having already completed 19,000km of 2-D data in two previous Great South Basin surveys.
Chief executive of the Petroleum Exploration and Production Association of New Zealand, David Robinson, welcomed the regime change and was confident the offer would attract both local and foreign interest from companies with deep water exploration expertise.
"However we are aware that there is some concern among the public of the risks of deep-water exploration," Mr Robinson said.
He highlighted a 40-year track record of successful offshore well completion in New Zealand, including deep water exploration.
The Government would also have in place new offshore drilling regulations and new environmental consenting regime by the time these permits reach the drilling stage, he said.
Three of the more than 20 zones around New Zealand being proposed for offer this year are off the coast of Wairarapa, the Wanganui Chronicle reported.
The first, East Coast 2, begins close to 9km offshore from Castlepoint and continues northwest past Akitio. The second and third, named for the Pegasus Basin, cover the seabed off the South Wairarapa coast, beginning just past the 19km limit to New Zealand's territorial waters.
The "block offers" are still subject to consultation with iwi and local government.
If oil or natural gas is found, the Government will take 42% of the profits.
Kevin Rolens, director of petroleum for Petroleum and Minerals New Zealand, said the Wairarapa blocks had been reserved from exploration for some years while the Government investigated their potential.
"We needed to inform ourselves; we do have an early appreciation of their potential."
Any exploration would be "very expensive" Mr Rolens said, and required "someone with deep pockets".
He said $100 million had been spent on the Great South Basin block below Stewart Island, although drilling had yet to begin.
Companies would need to be counting "in the millions of barrels of oil" to make their investment worthwhile.
