They said the plan ignores environmental implications and considers only economic ones.
Srisuwan Janya, president of the Stop Global Warming Association (SGWA), said the highway expansion inside the forest complex, a Unesco world heritage site, is designed to boost economic growth without taking into account environmental impacts.
He also urged the National Environment Board (NEB) and the National Council for Peace and Order (NCPO) to withdraw the project.
“An order to stop using the highway is the best way to protect and preserve the forest environment there,” Mr Srisuwan said.
He added that he will put the case to the Central Administrative Court if there is no positive response.
The NEB on Wednesday approved the EIA study for a combined wildlife corridor construction project which had been under consideration for many years.
Commenting on his Facebook page, environmentalist Vanchai Tantivitayapitak said he did not believe wild animals would use the man-made corridor to cross Highway 304, and the money spent on the project will be wasted.
He likened the project to the failed fish ladder project at the Pak Moon Dam in Ubon Ratchathani province.
“How do you know that the corridor will work for wildlife? Will they use it? Is there any study to support it?” he said.
He also said the project has been opposed by the Department of National Parks, Wildlife and Plant Conservation for many years due to environmental concerns. But the newly appointed NEB quickly approved the EIA study, reflecting the fact that the authorities are focusing only on economic development and ignoring environmental issues as they have the power to do so.
However, Kasemsun Chinnavaso, secretary-general of the Office of Natural Resources and Environmental Policy and Planning, said the EIA approval procedure was stringent. An expert committee had carefully studied the EIA and rejected it several times before finally giving its approval and forwarding it for the board’s consideration.
However, due to the political turmoil in the country, the board did not meet for a year. The meeting on Wednesday was the first this year and cleared long pending projects. Another 24 projects were also approved at the meeting, he said.
“All related agencies, including the national parks department, have been involved with the EIA study. We have not rushed to push the project through. The [new] cabinet will make a final decision on whether to go ahead with the project,” he explained.
A source from the Department of National Parks, Wildlife and Plant Conservation said that the department was unhappy with the environmentalists’ comments as the wildlife corridor must be built under the country’s commitment to the World Heritage Committee to limit wildlife deaths from car accidents and strengthen the biological environment.