Body of missing 18-year-old hiker Lily Hooper recovered in Nattai National Park

The body of an 18-year-old hiker has been recovered from dense bushland in a remote Australian national park more than a week after she went missing.

Lily Hooper had left her home in Sydney's southwest on August 12 to go hiking in Nattai National Park in the New South Wales Southern Highlands but did not return that evening.

When her vehicle was found abandoned at the start of the challenging 16km Bonnum Pic Walking Trail, authorities began an extensive search involving about 100 Australian Defence Force personnel and covering dense bush, steep slopes, and cliff edges.

The body of a woman, believed to be Ms Hooper, was located at 11.30am local time on Thursday, but the rough terrain hampered recovery efforts.

A NSW Police spokesperson said: “While yet to be formally identified, the body is believed to be that of the 18-year-old woman.”

However, Ms Hooper’s family were initially told she had been found alive.

Assistant police commissioner Joseph Cassar did not directly explain why the parents were initially told she was alive, but said there was “no playbook for communication”.

“I can tell you the police that was in charge at the time that spoke to Lily’s mum and dad certainly hoped for a more positive outcome,” he said. “If we are able to provide them more detailed information on that first report, I can tell you that would have been the case.”

“But unfortunately, it did take that small period of time for us to give them an update.”

Police Commissioner Mal Lanyon has "unreservedly" apologised for the error and for causing "any additional trauma" to Hooper's family.

On Friday, a spokesperson confirmed the body had been airlifted from the site, and a post-mortem examination will be conducted in the coming days to formally confirm the person's identity and determine the cause of death.

Australian prime minister Anthony Albanese described Hooper’s death as an “unspeakable tragedy”.

“Lily Hooper had so much more to offer the world,” Mr Albanese said.

“Her passing, I have no doubt, will be felt very deeply across the Southern Highlands, among her family, her friends, and indeed right across the nation.”