Australia's parliament will launch an inquiry into media ownership, a prominent senator said yesterday, after more than half a million people signed a petition demanding a probe into Rupert Murdoch's news dominance. The Australian arm of the New York-headquartered News Corp is the country's largest media organisation, owning papers in nearly every major city as well as cable television networks and magazines. The country's opposition parties united behind the move in the Senate to effectively sidestep the conservative government, which enjoys strong support from the Murdoch press and had not acted on the petition's demand for a royal commission.