Durras Community Association has written to NSW Environment Minister Matt Kean to express concern about the planned Murramarang Coastal Walk.
Association president Dr Trevor Daly said members were "seriously concerned" and were not consulted.
"According to the NPWS website, funding of $3.4 million has already been allocated to construct this walk, yet no social or environmental impact study has yet been completed or put on public exhibition," he said.
"No business case or cost-benefit analysis has been placed on the NPWS website or made publicly available to the community, that we are aware of. Bushwalking groups in this area, directly affected by the route, were neither consulted nor did they express a desire for further walking track development in Murramarang National Park."
He said the proposed route passed through several coastal villages, putting strain on pathways, public toilets, septic systems, viewing platforms, picnic areas and headland stairs: "What fees will the users of this walk pay to our local council and community to cover the wear and tear and maintenance costs?"
A National Parks and Wildlife Service spokesperson said: "The combination of nature and existing overnight accommodation in the coastal villages presents an exciting opportunity to create a new experience."
"(It) will provide a spectacular walk along coastline of Murramarang National Park and Murramarang Aboriginal Area and will be compatible with the parks' natural and cultural values, and will allow visitors to immerse themselves in the environment and enjoy the coastal villages.
"Effective community and stakeholder engagement is critical to the success of this project. The draft master plan is under way and will be available for public consultation in the near future.
"The open letter addressed to the Minister will be considered as a submission as part of the public consultation process. Interested stakeholders and community members will continue to be engaged in a meaningful and timely way."