Anadarko's $120million test drill of the Caraval prospect off the coast of Oamaru earlier this year proved unsuccessful.
The company will not surrender its permit but is stepping back to ship-borne hydrographic seismic testing before it commits to more drilling.
Confirmation of more deepwater Southern exploration has angered environmentalists, as three companies, including two large multi-nationals, expand efforts around their respective targets.
Anadarko's New Zealand corporate affairs manager, Alan Seay, said yesterday the next drill decision would be ''at least two years away'' - and entirely dependent on seismic results.
Exploration competitor New Zealand Oil and Gas is awaiting earlier seismic results from its prospects Clipper and Galleon (near Caravel) and will survey the Great South Basin prospect Toroa, south of Dunedin, during the first half of 2015.
Separately, oil sector services giant Schlumberger has just applied for a 446,000sq km prospecting permit covering the Great South Basin.
Anadarko had a deadline this week to notify its ''drill or drop'' intentions of a recently-extended five-year permit in the Canterbury Basin's southern sector, with Government permit agency New Zealand Petroleum and Minerals.
''We've advised Petroleum and Minerals that we're keeping the permit,'' Mr Seay said, meaning it had to commit to more exploration activities.
The January-March Caraval test well off Oamaru, in depths of 1100m and a further 1700m below the seabed, found ''shows'' of oil and gas, but not in commercially viable quantities.
''The [test drilling] results were disappointing, but the data was [otherwise] encouraging,'' Mr Seay said yesterday.
''All the requisites are there for finding hydrocarbons.''
He confirmed the seismic testing would not be around the earlier-drilled Caraval. The permit covers 17,492 sq km.
Six test holes since the 1970s, covering prospects Caraval, Carrack, Endeavour, Resolution and Barque off Oamaru, have been unsuccessful.
Anadarko spent about $400million using the drill ship Noble Bob Douglas offshore at Taranaki and Otago during 2013-14, with no commercial finds.
Mr Seay said the next step in the Southern programme depended on the availability of a seismic survey vessel. In the best-case scenario, a ship could be surveying by January-March next year, or the start of summer, in late 2015, he said.
No decision had been made on whether the seismic vessel would undertake 2-D or 3-D seismic testing, but if it was the latter, more detailed testing, it could cover an area of 3500sq km.
Previous similar-sized surveys in the Great South and Canterbury basins have ranged in cost from $7million to $10million.
ProGas Otago spokesman Andrew Whiley, also a city councillor, welcomed the fresh signs of confidence in the prospect of a find off the Otago coast.
''Obviously, they're excited about what's off our coast and the potential,'' he said.
But Oil Free Otago spokeswoman Rosemary Penwarden said Anadarko and other fossil fuel companies appeared to be ''pretty much in desperation mode'' and were still not welcome.
''They should expect resistance ... we don't want them, and we don't need them, and they should just not waste any more of their shareholders' time and money.''
