Australian police say they have freed a teenager trapped inside an upscale Sydney home for nearly 10 hours with a suspected bomb strapped to her body.

Police freed the young woman and reunited her with her parents, unhurt. A spokesman later confirmed that the there were no explosives in the device.

Police say Madeleine Pulver called them to say a man wearing a face mask entered her home in a wealthy Sydney suburb and put the device around her neck. Police describe the device as very sophisticated.

Police are searching for the suspect.

Australian media say the incident may have been an attempt to extort money from Pulver's parents, one of Australia's wealthiest families.