Police have apologised after the parents of a missing teenage hiker were told their daughter was alive, despite her body being found.

Lily Hooper, 18, was last seen around 8am on Wednesday morning when she set out on a hike in Nattai National Park in New South Wales from her home in Oakdale.

After an eight day multi-agency search, police found a body on Thursday around 11.30am which they believe to be Ms Hooper’s.

Assistant Commissioner Joseph Cassar said it was a SES volunteer who located the body in “thick, dense terrain”.

Her body is yet to be retrieved from the national park.

“The priority is focused on getting her out of that dense terrain and to reunite her with her family,” Mr Cassar told reporters on Thursday afternoon.

“There will be a coronial investigation which will be part of this process.”

Earlier this morning, it was widely reported that Ms Hooper had been “found alive”, which NSW Premier Chris Minns shared in a parliamentary hearing.

Soon after, he corrected himself.

“I’ve got some terrible news,” Mr Minns said, as published by The Guardian.

“I apologise … it seems as if the earlier advice was wrong.

“Lily’s body has been found.

“She’d been found deceased.

“This is obviously devastating, and I’m profoundly sad for her family and for all those concerned.

“I apologise.”

Mr Cassar confirmed that it was not just the Premier who had been delivered false information, but Ms Hooper’s parents, too.

“The initial information that the searchers believed she was alive and that was communicated (to the parents),” he said.

“But within eight to 10 minutes we were able to give them an update.”

Ms Hooper’s cause and time of death has not yet been determined and will form part of the investigation.

When asked what Mr Cassar’s message to the parents was regarding the miscommunication, he did not apologise.

“I think the only thing I can sincerely say is - my absolute condolences go out to Lily’s mum and dad,” he said.

“Everyone of the investigators and the searchers, whether the volunteers or head personnel, hoped for a more positive outcome.

“I can tell you the police that were in charge at the time had spoken to her mum and dad, certainly hoped for a positive outcome.

“If we were able to provide them more detailed information on that first report, I can tell you that would have been the case.

“Unfortunately it did take that small period of time was to give them...

“If I can turn the clock back I certainly—.”

Mr Cassar did not finish his sentence.

Later on Thursday afternoon, NSW Police Commissioner Mal Lanyon apologised to Ms Hooper’s family for the miscommunication.

“I unashamedly apologise for any additional trauma that may have caused Lily’s family,” he said.

“But certainly for the embarrassment and confusion that caused the miscommunication, obviously was born out of elation that Lily had been found.

“And certainly those at the command posts relayed, tragically, that miscommunication then led to a deflation, and obviously we know now and impact on her family.

“Once again, I unreservedly apologise for that miscommunication.”

Ms Hooper was last heard from when she reached the summit of Bunnum Pic around mid-morning.

That evening, the experienced bushwalker did not return and could no longer be reached, prompting a multi-agency search for the teenager.

Ms Hooper’s car was found at the Bonnum Pic trailhead on Wanganderry Road around 11pm but no further signs had been found of her.

Mr Cassar said the body was located “some significant distance” from where the car was found.

He added that “it wasn’t on a clear, walkable track”.

The Assistant Commissioner said he was “not aware who informed the Premier” of the update on the search.

Mr Lanyon said the Premier had apologised to him.

“The miscommunication obviously went through policing commands and up to government and has been reported widely,” he said.

“It was something that was inadvertent, but as I said, was borne out of looking to find Lily and bring her back to her family.

“It goes through a range of police commands to the minister for police and then to the Premier’s office.”

In Parliament on Thursday afternoon, both Prime Minister Anthony Albanese and Angus Taylor paid tribute to the teenager.

Mr Taylor acknowledged the initial reports which indicated Ms Hooper had been found alive.

“Initial reports that she had been found alive proved to be wrong, and that makes the blow even worse,” he said.

“We can only imagine what Lily’s family is going through right now.

“Such news would be a nightmare for any parent, and we grieve for Lily’s wider family and friends too.

“Lily loved bush walking, and that only compounds the tragedy of her death.”

The Prime Minister echoed those thoughts.

“Lily Cooper has been taken from her family, her community, and our nation far too young,” Mr Albanese said.

“The tragedy of a parent losing a young one, in Lily’s case just 18 years of age, is an unspeakable tragedy.

“Lily Cooper had so much more to offer the world.

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

He said his thoughts were with Ms Hooper’s family and loved ones on what he called “an incredibly sad and difficult day”.

The Prime Minister thanked the volunteers and emergency service personnel who were involved in the search for her.

It comes after almost 100 members of the Australian Defence Force joined the search for the teenager on Wednesday, in addition to 200 emergency services and defence personnel.