It is one of several options being considered by NZOG, in a regional report due for release mid-year, funded by the company, New Zealand Trade and Enterprise and ''other corporates'', a NZOG spokesman confirmed.
NZOG has a 50:50 stake with Beach Energy in the oil and gas prospect Clipper, about 60km off the coast of Oamaru, and has for the past 18 months been looking for a ''farm-in''; joint venture partner.
NZOG has until April next year to make a decision to either test drill the prospect by 2020, or relinquish the Clipper permit.
The spokesman said NZOG was continuing ''farmout'' discussions and several interested parties had signed confidentiality agreements.
''Those agreements are with more than a handful of operators ... who have the capability of working at those depths,'' he said.
He declined to reveal which companies were involved, or the corporates contributing to the regional report.
However, given the high costs and risks of exploration drilling in ''frontier'' basins, several of the major global companies would likely have to be among the interested parties.
Eight previous test holes in the area have not shown commercial viability since the 1980s.
The spokesman stressed more test wells, then development wells, would have to drilled in the area, in a timeframe spanning from 2020-25.
On the question of production facilities, he said a floating lng plant could cost billions and agreed building a new onshore facility in New Zealand would cost more than $1 billion.
''It will be good if we are able to show commercialisation [options] to the prospective farm-in [joint venture] partners,'' the spokesman said.
Elsewhere around the world there have been moves towards construction and use of large floating production storage and off-loading (FPSO) ships, which can anchor above an oil or gas find, upload the product and refine it at sea, to be offloaded to smaller tankers.
The spokesman said an FPSO ship was more suited to liquids than gas, which was thought to be most likely the product from Clipper.
A 2009 production plant in Taranaki had cost more than $1.1 billion, while Chevron had spent $A55 billion in Australia's northwest shelf, establishing a large production plant.
NZOG's regional report would be looking at not only plants, but gas buyers, which could include local industries and the dairy sector, where gas could be a more viable option than coal-fired energy sources, he said.
In its ''activities report'', NZOG outlined the process to return $100 million to shareholders, from the $168 million it got for selling its stake in the the Kupe field in Taranaki.
The spokesman believed the estimated capacity of Clipper was ''many times'' that of Kupe.
NZOG was at the end of March sitting on $234 million cash with expectations it would have about $113 million at the end of June.
NZOG's ''best estimates'' of the offshore Oamaru petroleum system total 11 trillion cubic feet of gas and 1.5 billion barrels of liquid, in oil or gas condensate form, with the actual deposits about 2500-3000m below sea level.
''A regional impact study is under way to determine the commercialisation pathways for liquids and gas to shore,'' the report said.
''Initial results from the study showed that gas-to-shore developments could also be highly commercial, with several potential gas buyers indicating their interest in supporting significant totals of gas supply,'' the report said.
NZOG also holds a separate 30% stake in the deepwater Toroa prospect, south of Dunedin, with Woodside Energy as operator holding 70%.
Subject to evaluations of the prospect being completed this year, a joint venture decision to drill a test well would be made by 2019-20.
