Opponents of petroleum drilling in Taranaki hope to stop a new round of exploration by convincing landowners to ban prospectors from their property.
The group Climate Justice Taranaki says the Crown has issued 13 onshore exploration permits in the region, and 15 more offshore, over the past few years.
Spokesperson Urs Signer says drilling chemicals can spoil groundwater, while drilling wastes spread onto land contaminate soil.
He told an anti-drilling meeting in Okato on Tuesday that prospecting permits generally last a year and if opponents block the seismic surveys they can stop subsequent drilling.
The industry body is calling on oil and gas companies to join forces to win over the public.
The Okato anti-mining meeting was attended by 40 people, and the Petroleum Exploration and Production Association says there have been similar-sized gatherings in Gisborne and Wellington recently.
The association's executive officer, John Pfahlert, says competing companies need to combine to win public support for the industry.
He says opposition has been spurred by a US documentary about water contamination from a process called fracking, in which underground rock is cracked with a high-pressure mix of sand, water and chemicals.
Mr Pfahlert says most fracking in New Zealand is carried out at least three times deeper than usable groundwater, and no large-scale production by thos method.