Senior Tory Sir Desmond Swayne has been condemned as "completely out of order" by Cabinet minister Michael Gove after claiming that Covid-19 statistics have been "manipulated".
Former minister Sir Desmond was interviewed by a US anti-vaccine campaigner and urged an anti-lockdown group to persist with their efforts, suggesting official data should not be trusted.
Mr Gove called for the New Forest West MP to issue a full retraction and apologise for his "unacceptable" comments.
Sir Desmond said he is a "most enthusiastic vaccinator" but has been a frequent critic of the Government's lockdown measures.
Sky News reported that in November Sir Desmond told the anti-lockdown group Save Our Rights UK that the figures were "bouncing round at the typical level of deaths for the time of year".
He said: "It seems to be a manageable risk, particularly as figures have been manipulated... We're told there is a deathly, deadly pandemic proceeding at the moment.
"That is difficult to reconcile with ICUs (intensive care units) actually operating at typical occupation levels for the time of year and us bouncing round at the typical level of deaths for the time of year."
This month Sir Desmond told US anti-vaxxer Del Bigtree that the UK has become "a police state" and accused the Government of attempting to implement "social control" through actions such as the mandatory wearing of face masks, Sky News said.
Cabinet Office minister Mr Gove told Sky: "Sir Desmond is wrong.
"I work with Sir Desmond, I have great affection for him, but I'm afraid here he is completely out of order."
He declined to say that Sir Desmond should have the Conservative whip removed but added: "I would hope that he issues a full and complete retraction and apology for what he said - it's unacceptable."
Deputy Labour leader Angela Rayner has written to Conservative Party chairwoman Amanda Milling about Sir Desmond's comments.
She said the Tory MP "endorsed conspiracy theories about the veracity of the disease".
"He also suggested the official figures have been manipulated - a deeply dangerous claim for which there is absolutely no evidence.
"The seriousness of his actions cannot be understated. For a Member of Parliament to appear on this platform and undermine our fight against the pandemic could have truly devastating consequences.
"Following Desmond Swayne's shocking refusal to apologise for his behaviour, I urge you to make clear what action you will take. It is the duty of all of us to support the national effort to vaccinate Britain."
Imran Ahmed, chief executive of the Centre for Countering Digital Hate (CCDH), which has been investigating online misinformation about coronavirus and vaccines, said Sir Desmond's words had given "legitimacy to crank anti-vaxxers".
"This MP's judgment needs to be seriously questioned when, by virtue of association, he lends legitimacy to crank anti-vaxxers and peddlers of falsehoods about Covid," Mr Ahmed said.
"When we wear a mask or get vaccinated, we don't just protect ourselves, we also protect those we love, the community we spend time in, and in turn help secure our country against coronavirus.
"While Covid continues to kill, turning science into a political football is a Trumpian act of grotesque irresponsibility."