Teenage bushwalker Lily Hooper has been found dead in a rugged national park south-west of Sydney.

Nearly 100 soldiers have joined the search for missing Sydney bushwalker Lily Hooper.

Lily Hooper was found on Thursday morning, more than a week after she went missing in dense bushland.

Lily Hooper had been missing in bush near Sydney for eight days.

Lily Hooper, 18, disappeared while hiking in Nattai National Park