The search for an experienced teenage hiker missing in a national park is continuing four days after she was last seen.

Search teams relaunched efforts to find 18-year-old Lily Hooper in Nattai National Park, in the NSW Southern Highlands, about 7am on Saturday.

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Hooper left her home on Burragorang Rd in Oakdale about 8am on Wednesday to go hiking in the national park but has not been seen since.

The only clue to her whereabouts has been her car, which was found about 11pm on Wednesday at the beginning of the Bonnum Pic walking trail along Wanganderry Rd.

NSW Police Detective Inspector Benjamin Carey described Hooper as an “experienced bushwalker for someone of her age”.

“She does regularly engage in bushwalks, some quite challenging and it is one of her favourite recreational pastimes,” he said.

Police enquiries suggest Hooper may have reached the summit of Bonnum Pic mid-morning on Wednesday but has not been heard from since.

Some of Hooper’s family members and friends have been joined by multiple agencies in their search effort, including local police, police rescue, drones, an ambulance helicopter, SES officers and firefighters.

While those efforts have scoured the walking trail and the broader national park, there has been no sign of the teenager.

Lily’s aunt, Sheridan Munro, said the family was “desperately trying to find her”.

Carey said the family is “very, very distraught” and police are “doing everything we can to support them in this challenging time”.

“We are very hopeful that Lily is still alive and we are focusing our efforts on searching for her today and hopefully delivering that outcome,” he said.

A search in the Nattai National Park for missing teenage bushwalker Lily Hooper has continued on Saturday. Credit: NSW Police

According to the teenager’s social media, she returned last week from Thailand, where she had been taking Muay Thai lessons.

NSW Premier Chris Minns said he was “praying for good news” as the search continued.

“Our heart goes out to that young walker’s family,” he said. 

“We know this must be heartbreaking and incredibly anxious.

“I’m praying for good news.”

Lily is described as being of Caucasian appearance, about 175cm tall, of slim build, with long blonde hair and blue eyes.

She was last seen wearing a shirt and shorts.

Anyone with information on Lily’s whereabouts, or walked the Bonnum Pic Walking Trail since Wednesday, is urged to contact Moss Vale Police Station or Crime Stoppers.