Himalayan Niti Abhiyan, in a letter to International Union for Conservation of Nature (IUCN) in Switzerland, have said that they oppose the move since locals, who are forest dwellers, depended on the area for their livelihood.
Experts from IUCN had recently visited Great Himalayan National Park for its possible inclusion in 2013's World Heritage List.
Coordinator of the Abhiyan, Guman Singh, said the NGO's local group had also spoken regarding the matter to the IUCN team which had visited the national park in October this year.
"They had met the team under the leadership of Dila Ram and questioned the stake of some outsider NGOs in the park and expressed the concerns of local communities, who are enjoying forest rights here since centuries," he said.
He said that the NGO had asked the UNESCO team led by Graeme L Worboys regarding what will be the locals' stake if the national park is given world heritage status.
"What will happen to their traditional forest and cultural rights in the park area and what benefits will be provided to us after this world heritage status", he said.
Local people are struggling for the protection of our traditional forest, cultural rights, he said.