State government has bought the $2.8 million Radiata Plateau

A 35-year long campaign by the Blue Mountains Conservation Society to see Radiata Plateau become part of the Blue Mountains National Park has been successful, after the state government announced it had purchased the site for about $2.8 million.

The land purchase protects the last remaining undeveloped peninsula-plateau on the upper Blue Mountains western escarpment.

The 306 hectare property went on on the market for $2.8 million in June.

Environment Minister Matt Kean announced on the long weekend Monday that Radiata Plateau would be incorporated into the state's national park reserve system, ensuring its protection for future generations.

"We have just exchanged contracts for this important 300 hectare parcel of land, which will help secure this beautiful landscape forever," Mr Kean said.

"The NSW government has been working towards acquiring this private property over recent months to ensure it is protected."

Mr Kean said when he first became environment minister he was determined to expand the parks footprint by 200,000 hectares, something that "horrified" some national party members.

"I'm not going to be an environment minister that gets rolled on the environment," he told the Blue Mountains Gazette.

He thanked the the community and the Blue Mountains Conservation Society for their three decade long campaign to ensure the land was protected. His "mate" [Labor MP for Blue Mountains] Trish Doyle and his Liberal colleague Shayne Mallard had encouraged him to visit the site and he also flew over in a helicopter to appreciate it.

Blue Mountains Conservation Society president Tara Cameron said, wins in the conservation movement were rare, so they were delighted by the news and congratulated the minister.

"This landmark decision is a major win for the environment, and for the Blue Mountains community.

"Our latest campaign, Leave Radiata Plateau Wild, garnered very strong community and environmental support. Community members wrote letters, attended rallies, participated in videos, hung banners and placards, and did so much more to advocate for the protection of this unique area. We couldn't have asked for a better outcome."

The site supports wildlife corridors and endangered species such as the Spotted-tailed Quoll, the Greater Glider, Flame Robin, the Dwarf Mountain Pine, Glossy Black Cockatoo, and Gang-Gang Cockatoo.

Mr Kean said he received hundreds of letters from residents who enjoyed the network of tracks with options for birdwatching, bushwalking and climbing.

The property is significant to the Gundungurra and Dharug people and includes the state heritage listed 'Blacks Ladder', a traditional pathway into the Megalong Valley. The National Parks and Wildlife Service will develop a plan of management for the site.

Last year more than 30 groups and community leaders signed an open letter to then Environment Minister Gabrielle Upton calling for Radiata Plateau to be bought by the government. The Berejiklian government made an election promise to review the proposed acquisition. Labor said it would negotiate to buy land at the plateau to add to the national park if it won the election.

Blue Mountains MP Trish Doyle said: "I am delighted to see the NSW government honouring Labor's commitment to the Blue Mountains National Park and buying the Radiata Plateau from private owners. When we got wind that the property was going to become available for sale for the first time in some 30 years, we knew we had to act quickly and decisively."