Duynhoven yesterday afternoon confirmed Crown Minerals was offering 40 new GSB petroleum exploration permits, each about 9000 square kilometres in size, off the southeastern coast of Otago and Southland.

“The Great South Basin has long been regarded as a region with enormous exploration potential,” he said.

“It is a frontier region where the potential for high reward is matched by high risk in terms of exploration costs and challenging sea and weather conditions.

“We are therefore offering large blocks that will provide companies with the scope of opportunity needed for the exploration commitment we are seeking.”

Crown Minerals had consulted extensively with exploration companies around the world to establish bidding terms that would attract the best possible bids.

Last March, it conducted a 3200km 2D seismic survey of the basin, with the data freely offered to companies in the lead-up to the bidding process.

“Initial processing of the seismic data has revealed new signs of oil and gas and the size of the basin appears to be far larger and more extensive than previously thought,” he added.

“Although the Great South Basin is a proven petroleum system, it will require several years of exploration before the full potential of the basin is properly understood.

“We therefore need to attract companies with good technical skill, significant financial capability and the right exploration strategy to provide us with the best chance that the basin can contribute to New Zealand’s energy future.”

Crown Minerals group manager Adam Feeley said the GSB blocks offer was the biggest and most exciting he could remember.

Duynhoven said several major oil companies had already indicated interest in the GSB and that Crown Minerals would continue promoting the acreage in North America, Europe and Asia in the coming months. Bidding would close next March.

PetroleumNews.net has reported that only a dozen or so of the major oil companies have the financial and technical capabilities to hunt successfully for oil and gas in the GSB. Only mega trillion cubic feet (Tcf) gas finds or 100 million barrel-plus oil strikes will be economic, given the harsh conditions and lack of energy infrastructure in the lower South Island.

ExxonMobil, which bought extensive seismic data over part of the GSB, and Royal Dutch Shell are believed to be among the likely bidders.

Perth-based junior Bounty Oil, which earlier this year unsuccessfully fought against Crown Minerals’ revocation of its GSB licence PEP 38215, estimates the basin could contain hydrocarbon reserves worth about $US800 billion ($A1.04 trillion).

“This is perhaps the most exciting development in oil and gas exploration in New Zealand since the discovery of Maui [a 3Tcf gas-condensate field found in 1969],” Duynhoven concluded.