The Morrison government is under increasing pressure to stop two of its MPs spreading dangerous coronavirus misinformation.
Prime Minister Scott Morrison, his deputy Michael McCormack and Health Minister Greg Hunt have refused to publicly condemn Liberal MP Craig Kelly and the Nationals' George Christensen.
Top government leaders have pointed to free speech when challenged about coronavirus and other conspiracy theories shared on the backbenchers' Facebook pages.
Former prime minister Malcolm Turnbull said free speech was not a reason to let statements go unchallenged.
"What Morrison and McCormack and Hunt should be saying at the very least is that Craig Kelly is wrong and that it is reckless and irresponsible to be misleading the Australian public on matters of public health," he told the ABC on Wednesday.
The Australian Medical Association is calling on the federal government to launch an advertising campaign against health misinformation.
AMA president Omar Khorshid said people in positions of power could deliver online misinformation which others could easily absorb.
"We have seen this with the anti-vaccination movement and the countless conspiracy theories about the COVID-19 pandemic that circulate constantly on the internet," he said.
Labor has demanded senior cabinet figures condemn the coalition duo who are refusing to take a backward step.
Opposition health spokesman Chris Bowen said Mr Kelly had made a systemic and deliberate attempt to undermine medical health professionals.
"Craig Kelly is a menace and at every turn, Scott Morrison and now Michael McCormack, acting prime minister, have failed to call him out," he said.
Mr Kelly on Tuesday fired off a fresh barrage of posts championing Ivermectin, an unproven coronavirus treatment Facebook warned him over last week.
Mr Hunt wouldn't be drawn on Mr Kelly's accusation health officials had engaged in child abuse for encouraging face mask use.
"There will be different views from different people," the health minister said.
But Mr Hunt argued Australia's success in combating coronavirus stemmed from governments acting based on expert health recommendations.
"Our advice comes from what I believe are the best medical advisers in the world. That's what's protected Australia and that's what we're going to continue to do," he said.
"I would urge everyone to listen carefully to the advice of the Australian medical regulators and Australian government medical advisers."
Meanwhile, the Queensland government is shutting down a quarantine hotel after six people on the same floor tested positive for the highly contagious UK virus strain.
NSW recorded one new locally acquired case linked to the Berala cluster on Wednesday.
