A large palm oil plantation project in development in Cameroon since 2010 will put livelihoods and ecosystems in peril if allowed to continue, a US-based think-tank warned Wednesday.

"With the loss of livelihoods by thousands of Cameroonians on the line and critical and unique ecosystems in peril, this project must be stopped," the Oakland Institute said in a report Wednesday.

Authoured in collaboration with Greenpeace International, the report said the project from SG Sustainable Oils Cameroon (SGSOC) was a case of massive deforestation disguised as a sustainable development project.

In 2009, Cameroon granted SGSOC, a subsidiary of US firm Herakles Farms, over 73,000 hectares (180,000 acres) of land in the country's southwest to develop the plantation and refinery through a 99-year land lease.

But much of the project area is in a "biodiversity hotspot" that "serves as a vital corridor between five different protected areas," the institute said.

It added that many locals fear the plantation would "restrict their access to lands held by their ancestors for generations" or that they would "lose land for farming as well as access to critical natural resources and forest products."

In April, "11 of the world's top scientists issued an open letter urging the Cameroonian government to stop the project that they say will threaten some of Africa's most important protected areas," the think-tank said.

But Bruce Wrobel, CEO of Herakles Farms, told the institute that "our project, should it proceed, will be a big project with big impacts -- environmentally and socially."

"I couldn't be more convinced that this will be an amazingly positive story for the people within our impact area," he was quoted saying in the report.