Google responded quickly, saying it was "deeply disappointed" with the proposal.
"The government's heavy-handed intervention threatens to impede Australia's digital economy and impacts the services we can deliver to Australians," said Mel Silva, Google's managing director for Australia and New Zealand.
Facebook issued a terse one-line response that hinted it could reconsider its activities in Australia if the proposals were implemented.
"We are reviewing the government's proposal to understand the impact it will have on the industry, our services and our investment in the news ecosystem in Australia," said Will Easton, Facebook's local manager.
The initiative has been closely watched around the globe as news media worldwide have suffered in an increasingly digital economy, where advertising revenue is overwhelmingly captured by Facebook, Google, and other Big Tech firms.
The crisis has been exacerbated by the economic collapse caused by the coronavirus pandemic, with dozens of Australian newspapers closed and hundreds of journalists sacked in recent months.
Unlike other countries' so-far unsuccessful efforts to force the platforms to pay for news, the Australian initiative uses competition law and not copyright regulations to challenge what Australia calls an "acute bargaining power imbalance" between media and the US giants.
'We want it to be fair'
The move has been strongly pushed by Australia's two biggest media companies, Rupert Murdoch's News Corp and Nine Entertainment, who stand to gain the most from the crackdown.
News Corp Australasia executive chairman Michael Miller called Friday's announcement a "watershed moment" and declared the "platforms' days of free-riding are ending".