Source: Niamh Harris

Over 500,000 Australians have signed a petition calling for an inquiry into Rupert Murdoch’s powerful, global media empire.

The petition to parliament was launched by former Australian Prime Minister Kevin Rudd just over three weeks ago and closed this week on Wednesday.

CNN reports: It calls for a Royal Commission — Australia’s highest form of public inquiry — to “investigate threats to media diversity.” It also accused media businesses of encouraging “deliberately polarizing and politically manipulated news.”

While the petition raised several points of concern, including Google (GOOGL) and Facebook’s (FB) relationship with the news media, it singled out Murdoch’s News Corp (NWS) as a potential threat to free speech and public debate.”

We are especially concerned that Australia’s print media is overwhelmingly controlled by News Corporation, founded by Fox News billionaire Rupert Murdoch, with around two-thirds of daily newspaper readership,” the petition said. “This power is routinely used to attack opponents in business and politics by blending editorial opinion with news reporting.”

News Corp Australia did not immediately respond to a request for comment. The publisher is one of the largest in the country and owns major nationalnewspaper The Australian and tabloids such as The Daily Telegraph and The Herald Sun.

Rudd usedsocial media to tout the responseto the petition.

“Half-a-million Australians have spoken. They’ve smashed the records to make their voice heard: Australia needs a #MurdochRoyalCommission to protect the lifeblood of our democracy,” he said in a tweet.

The petition will likely be presented to Australia’s House of Representatives, but lawmakers arenot obligated to act on it.

Rudd has been outspoken about what he considers the toxic influence of Murdoch’s media properties.

He has called the billionaire’s news empire a “cancer on democracy” in the United States, United Kingdom and Australia, and likened the organization to the mafia in an interview with CNN chief media correspondent Brian Stelter in May.

“To call the Murdoch media empire a journalistic organization committed to bringing you fair and balanced news coverage around the world these days has become a joke,” Rudd said.