The National Parks and Wildlife Service is trying to track down the climate change activists who climbed one of the Three Sisters to drape a banner in support of their cause.
The climbers scaled the site 10 days ago to unfurl their banner about climate change action.
Blue Mountains Regional Manager of NPWS Alan Henderson said climbing the site is an offence under the National Parks and Wildlife Act.
"Climbing is banned on the Three Sisters as a mark of respect for Aboriginal cultural heritage and to protect it from erosion," he said.
"For Aboriginal people, the Three Sisters is a spiritual place of ancestors and a mythical site of legends and stories.
"The Gundungurra people tell one story of how three sisters fell in love against traditional lore and another tells how there were originally seven sisters and not just the three seen here today."
Mr Henderson said the importance of the Three Sisters was reinforced when it was declared an Aboriginal Place last January.
"NPWS manages the Aboriginal Place within Blue Mountains National Park in partnership with the local Aboriginal Community," he said.
Climbing has not been permitted on the Three Sisters since 2001 and the rock-climbing community has largely respected the ban.
Blue Mountains MP, Roza Sage, said she had been contacted by Gundungurra Elder Aunty Sharyn Halls, who was upset when she saw that the renowned land formation had been used as a political tool.
"It's a special place of deep spiritual significance for our local indigenous people," she said.
Mrs Sage said whoever put the banner up should apologise and should also pay for the cost of removing it.
Aunty Sharyn Halls said the Three Sisters was a very special place to her.
"I'm disappointed that those responsible had to go onto an iconic Aboriginal site to get their message across," she said.
Anyone with information is asked to contact the NPWS on 4787 8877 or email firstname.lastname@example.org.