More than 100,000 people have signed a petition by former Australian PM Kevin Rudd calling for an inquiry into Rupert Murdoch's media dominance in Australia. Mr Murdoch's company News Corp Australia controls about 70% of the nation's print circulation. Mr Rudd said a top inquiry should scrutinise media ownership but particularly Mr Murdoch, calling him "a cancer on our democracy". News Corp Australia and Mr Murdoch have not commented on the petition. The company has often defended its reporting against accusations of political bias, racism and climate change scepticism. Mr Rudd posted the petition on a parliamentary website on the weekend and said an "avalanche of support" for it had briefly overwhelmed IT systems.