A body believed to be that of a missing man has been found in the Stirling Range national park in Western Australia's south.

Police say they discovered the body near Mt Toolbrunup during an extensive search for 26-year-old Muhammad Ferdiansah.

Mr Ferdiansah's family have been informed of the discovery and police intend to retrieve his body on Monday.

Authorities had deployed a helicopter and drones along with local police and SES volunteers to search for Mr Ferdiansah after his car was found abandoned at the Mt Toolbrunup carpark.

The national park in WA's Great Southern region is home to some of the state's highest mountain peaks.