Bones have been found in bushland south of Sydney in the search for missing man Matthew Leveson.

The discovery was made on Wednesday afternoon, almost a week after police started searching a site in the Royal National Park.

A backhoe used in the searches stopped before police and Mr Leveson's family were called over to an area just off the road near Waterfall.

The bones are thought to be human but forensic testing will need to establish whether they are and whether they belong to Mr Leveson or not.