Austrian company OMV confirmed on Friday it would arrive off the Otago coast this summer to drill a one-off oil and gas exploration well costing around $80million.
The COSL Prospector oil rig is being used in Taranaki, and will then head to the Great South Basin to drill a well about 146km southeast of Balclutha.
Last week an OMV spokesman told the Otago Daily Times the success rate for the industry was only about 15% and it was likely nothing would be found.
Oil Free Otago spokeswoman Rosemary Penwarden said the company's travels to the Great South Basin "screamed of desperation".
"Why are they even bothering?"
However, the group's message was even a little exploration was too much.
"Even a single exploratory well could go very wrong. We don't want that risk. We cannot burn most of the oil and gas that is already discovered."
Ms Penwarden was in Wellington on Friday attempting to hand-deliver a letter to OMV's New Zealand-based exploration and appraisal manager Alan Clare.
"It was telling them to relinquish work in the Great South Basin or they will be resisted every step of the way."
She was unable to deliver the letter except to a cafe in the lobby, as his floor was in "constant lockdown".
Dunedin City councillor Mike Lord said after the news exploration was confirmed he welcomed the company with "open arms".
Natural gas would help companies like Fonterra, which burned coal, to switch to a relatively clean energy source, he said.
"If we can leave coal in the ground and use gas, I would have thought that was a good thing," Cr Lord said.
"Wouldn't it be a game changer if we could get a gas source off our coast?"
It "would be nice" to transition to cleaner energy sources, but it was not something which could be done overnight, he said.
An Environmental Protection Agency hearing will be held in Dunedin on July 30 relating to the plans.
However, the hearing is limited to the discharge of harmful substances from the hazardous and non-hazardous deck drains aboard the drill rig.
From Otago and Southland 29 submitters on the plans indicated they wished to speak at the hearings.
