Body of teen hiker found eight days after disappearing

A body has been found in the search for a teenager hiker who went missing in a national park more than a week ago.

Lily Hooper went missing on August 12 after embarking on a hike in the Nattai National Park in NSW's Southern Highlands.

The 18-year-old from Oakdale, in Sydney's southwest, did not return that evening and could not be contacted on her mobile phone, triggering a wide-scale search by emergency services.

Authorities found the body, which has not yet been formally identified but is believe to be Ms Cooper, in bushland about 11.30am on Thursday, NSW Police said in a statement.

Ms Hooper had not been seen since her car was discovered at the Bonnum Pic trailhead on Wednesday night.