Austrian oil explorer OMV and Greymouth Petroleum gave a rare glimpse today into the improving state of knowledge about one of New Zealand's most talked-up but under-explored offshore areas, the Great South Basin.

In presentations to the biennial Crown Minerals Petroleum Conference in Wellington, Greymouth's chief executive Mark Dunphy and OMV NZ's exploration manager John Anderson showed normally commercially sensitive slides indicating the kinds of plays that are emerging as a result of recent seismic acquisition campaigns.

OMV has more than doubled the seismic coverage of its GSB permit area since 2008, and found numerous examples of potential hydrocarbon-bearing structures including non-marine deposits, transgressive sands, and deep marine turbidite fans.

The size of the GSB permit area and its inclement weather, along with the comparatively small amounts of data collected on the whole area are all significant challenges to further development, says Anderson, who gave no hint as to OMV's next steps in the permit.

However, for such large, frontier exploration permits, he believes permit-holders need longer than the current five years to complete a full programme of investigation.

The importance of further major gas finds for security of electricity supply was a constant theme through the first day of the conference.

Origin Energy's executive GM for upstream oil and gas, Paul Zealand, says the industry needs to be thinking now about "options for commercialisation of new gas discoveries, especially for Maui-sized of bigger.

His comments echoed advice from international speakers who urged New Zealand both to step up its pace of exploration, especially given the explosion in liquefied natural gas exports to Asia planned from Australia, and to plan ahead for the likelihood of a major gas find in one of the many offshore basins that New Zealand has yet fully to explore.

Origin has prospecting interests in the Canterbury Basin, which it is developing with deep-sea drilling experts Anadarko, and is "optimistic about the potential" although Zealand says it's still "early days".

A huge gas find in New Zealand could lead to the creation of an LNG export industry, while smaller finds could help secure electricity supply into the future.

Meanwhile, Dunphy called for domestic gas market intervention, accusing gas pipeline owners of allowing wholesalers to use transmission pipelines for gas storage rather than delivery - a clear dig at Vector and the gas transmission bottleneck currently holding wholesale gas prices up in the Auckland market.

Dunphy scotched current talk of over-supply in the natural gas market, saying there was only "contractual indigestion" at present, with NZ still facing a long term gas shortage, which means "offtake counterparties won't make capital commitments".

He reprised arguments about the failures of the Gas Industry Company and the current co-regulation model, which he said is "simply not working".

"Intervention is required to address these processes and it may need to be retrospective."

However, Dunphy believes there is "vast undiscovered" deep gas in the Taranaki Basin, let alone in the Great South Basin, where Greymouth holds permits.

Dunphy says Greymouth holds around 8 - 10 per cent NZ gas market share at present and is targeting becoming number two here. On the basis of recent trends, the company might expect to have secured reserves of around 160mboe by 2015, with production of perhaps 40mboe by then.

However, its prospects in Chile are also promising, and Greymouth expects that it will be earning half its outcome from Chile over time.