In a statement on Monday, it also urged the government to stop being “stubborn” and scrap the project right away.
The remarks follow a report published on the website of UNESCO World Heritage Committee on Sunday.
The proposed coal-fired power plant at Rampal near the Sundarbans in south-east Bangladesh was discussed at the UNESCO World Heritage Committee's meeting in Poland in July.
The Sundarbans, a world heritage site, is the largest mangrove forest in the world.
According to the outcome of the meeting, the UN agency insists that Bangladesh government carry out a strategic environmental assessment or SEA before proceeding with any kind of development work.
The statement has come in contradiction to the government’s previous claim that the UNESCO had withdrawn its objection to Rampal plant.
The prime minister’s Energy Adviser Tawfiq-e-Elahi Chowdhury briefed the media on Monday when he said that the government would go ahead with the Rampal power plant by mitigating the UNESCO's concern.
Oil-gas committee Convener Sheikh Muhammad Shahidullah and Member Secretary Anu Muhammad issued a statement the same day.
“Respect scientific research, expert opinions and the growing public opinion and scrap the Rampal deal immediately,” reads the statement aimed at the government.
The Awami League government signed an agreement with India to jointly set up the Maitree Super Thermal Power Plant at Bagerhat's Rampal in 2016.