NSW man may have known his kidnappers

A man who says he was thrown into a car boot, assaulted, then dumped in bushland in Sydney's west may have known one of his kidnappers.

The 40-year-old told police he was threatened by three men armed with knives and shoved into the back of his vehicle when he went to check on his car in the underground car park of a Mt Druitt unit block early on Sunday.

He was beaten and forced into the boot of a second car and abandoned after being punched and kicked in the face in bushland in the nearby suburb of Shalvey.

Police say they believe the victim may have known one of his attackers as they continue their search for the trio.