Morrison, who met with a number of tech firms Tuesday — including Facebook, Twitter and Google — said Australia would encourage other G20 nations to hold social media firms to account.Attorney-General Christian Porter said the new laws would make it a criminal offence for platforms not to quickly take down "abhorrent violent material" like terror attacks, murder or rape. Executives could face up to three years in prison for failing to do so, he added, while social media platforms — whose annual revenues can stretch into the tens of billions — would face fines of up to ten percent of their annual turnover. "Mainstream media that broadcast such material would be putting their licence at risk and there is no reason why social media platforms should be treated any differently," Porter said. The government was so far "underwhelmed" by the response from tech giants at their Tuesday meeting with Morrison, communications minister Mitch Fifield told reporters Saturday. But cyber-security expert Nigel Phair, from the University of New South Wales, cast doubt over the ability of proposed Australian laws to impose jail time. "The penalty is only for Australian domiciled executives, and on the whole they´re marketing executives, not those responsible for running and maintaining the platform," he told broadcaster SBS earlier this week.