Tens of thousands of African elephants are under threat from plans for a massive new oilfield in one of the continent’s last great wildernesses, experts have warned.

Campaigners and conservationists fear the proposed oilfield stretching across Namibia and Botswana would devastate regional ecosystems and wildlife as well as local communities.

“It is incomprehensible that ReconAfrica’s hunt for fossil fuels is going ahead,” said Rosemary Alles from Global March for Rhinos and Elephants. “Fewer than 450,000 elephants survive in Africa, down from millions not so long ago: 130,000 of these have established this region as a home range, and ReconAfrica’s misbegotten plans place them at direct risk.” ReconAfrica, a Canadian oil and gas company, listed on stock exchanges in Canada, the US and Germany, has leased more than 34,000sq km of land in the Kavango Basin. Seismic exploratory work has begun, and experts say the new oil field could be one of the biggest of recent years. ReconAfrica estimates that the “potential oil generated” could be between 60 billion and 120 billion barrels – and be worth billions of dollars to the regional economy.

The Namibian government said only exploratory licences had so far been granted which did not allow any production operations. It said the exploratory wells were not located in any “conservancy or environmentally sensitive area and will have no significant impact on our wildlife”.