Police are investigating a purported recording of Sydney property developer Salim Mehajer threatening a business owner, calling him "a Shia dog" and threatening to attack his mother.

Channel Seven said on Tuesday that it obtained the recording of Mr Mehajer threatening the owner of Queen St Customs, a prestige car hire and smash repair business in Revesby.

Mr Mehajer reportedly had a dispute with the owner over a car.

A NSW Police spokeswoman told Fairfax Media: "Police from Bankstown Local Area Command are aware of the matter and are investigating."