"It does not matter what an international body or organisation said about the project," said BNP leader Ruhul Kabir Rizvi during a human chain programme in Dhaka on Friday.
"Our party supports the campaign by our experts and intellectuals who have warned against the negative impacts this coal-fired plant will have on the environment. Some Indian researchers are also concerned about its effects on both humans and animals."
The government signed an agreement with India to jointly set up the Maitree Super Thermal Power Plant at Bagerhat's Rampal in 2016.
It has since been rejecting protests by environmental activists who have warned against the threat to the Sundarbans, the world’s largest mangrove forest.
On Thursday, the government announced that the UNESCO, which had opposed the plant's location near the Sundarbans, a world heritage site, endorsed the project during its 41st session of the World Heritage Committee in Poland.