The Australian Senate has passed a motion calling on the NSW government to give traditional owners more time to respond to the Warragamba dam wall-raising proposal.
The motion, co-sponsored by the Greens and Labor, also called for genuine consultation with the community.
"Overwhelming community opposition to the Warragamba dam proposal at the very least warrants longer, genuine consultation from the NSW government," said NSW Greens Senator, Dr Mehreen Faruqi, "but they have only been interested in appeasing developers while completely ignoring community concerns.
"The raised dam would flood world heritage-listed areas of the Blue Mountains and a number of Aboriginal cultural heritage sites, yet traditional owners have not been given enough time to assess the impact of this proposal.
"Raising the Warragamba dam wall is a disastrous plan to drown thousands of hectares of World Heritage national park, destroy Aboriginal cultural and spiritual sites, and damage our internationally recognised wild rivers," she said.
She believed the NSW government should drop the project.
Traditional owners had been given just 40 days to respond to a 2000-page report.
Federal Member for Macquarie Susan Templeman said she was "very pleased to see the Senate recognise the importance of allowing traditional owners more time to consider the report. It's imperative that there's genuine consultation with the community on the NSW Government's proposal."
Blue Mountains Greens councillor Kerry Brown said: "I am thrilled that Senator Faruqi's motion has been supported by the Senate.
"France and much of the world went into meltdown when 900-year-old Notre Dame cathedral burnt down but our state government apparently has no problem destroying a 300 million-year-old landscape that enshrines the sacred heritage of the oldest living culture on earth."
Cr Brown said she had attended a recent community meeting about the state government's "token cultural assessment process" and heard the powerful words of Gundungurra elders and young people.
"They are devastated by the state government's disrespect for them and their heritage."
Fellow Greens councillor, Brent Hoare, said: "Either the State Government is serious about consulting Aboriginal people or they are not.
"If they ignore this Senate motion and continue to push this destructive proposal through in spite of all the concerns and opposition expressed by the community, by scientists, by the international World Heritage body and by local traditional owners, it will be unarguable that developers continue to pull the government's strings."
Last month, Indigenous groups criticised the draft Aboriginal cultural heritage assessment report forming part of the environmental impact study for the wall raising proposal.
Gundungurra Elder Aunty Sharyn Halls from Katoomba and Warragamba resident and Gundungurra woman Kazan Brown said only 26 per cent of the affected area had been surveyed for cultural artifacts and sites.