A specialist unit has been set up by ministers to counter disinformation about coronavirus.
The government says the unit will work with social media companies and communications experts to limit the spread of false claims.
Culture Secretary Oliver Dowden said: "Defending the country from misinformation and digital interference is a top priority."
Meanwhile, the prime minister has chaired an emergency Cobra meeting to decide whether to bring in measures to delay the spread of coronavirus in the UK.
The Department for Digital, Culture, Media and Sport said teams across Whitehall had been brought together into a unit to "help provide a comprehensive picture on the potential extent, scope and impact of disinformation" on coronavirus.
Mr Dowden said they had brought expert teams together "to make sure we can respond effectively should these threats be identified" in relation to the spread of the Covid-19 virus.
"This work includes regular engagement with the social media companies, which are well placed to monitor interference and limit the spread of disinformation, and will make sure we are on the front foot to act if required," he said.
But Labour's shadow culture secretary Tracy Brabin said her party had been warning the government "for weeks" that online disinformation about the virus needed to be combated.
She said it was "time for the government to stop dragging its feet on online harms and introduce robust, comprehensive measures for curbing the spread of fake news".
Facebook has already said it has taken steps to combat the spread of misinformation about the virus.
The firm has third-party fact-checkers, who investigate dubious claims, and when they rate information as false, the company limits its spread across Facebook and Instagram.