The England and Wales polling watchdog has recommended delaying May's local elections until the autumn to "mitigate" the impact of coronavirus.
The Electoral Commission said there were "growing risks to the delivery of the polls", with the number of infections in the outbreak rising.
Mayoral and local elections are due to take place on 7 May in England.
Constitution Minister Chloe Smith said the government was still "working to facilitate" them.
She added: "We continue to work closely with those delivering the elections, while being guided by the evidence and latest advice from medical experts."
Voting is also due to take place on 7 May in England and Wales for police and crime commissioners.
So far, 10 people in the UK have died after testing positive for coronavirus, with 596 cases confirmed.
In its letter to the government, the Electoral Commission said it had "become clear that the risks are so significant as to raise serious concerns about the polls continuing to their current timetable".
It was "vital that voters are able to hear the positions of candidates, parties and campaigners before they cast their vote".
The letter also said: "While increased access to post and proxy voting may provide a partial solution for some electors, it would create further and additional pressures and risks in other parts of the system."
Prime Minister Boris Johnson has called coronavirus the "worst health crisis in a generation".
The government has also issued new measures, including asking people who experience a new continuous cough or a higher temperature to stay at home for seven days.
Speaking in Downing Street, Mr Johnson said: "There is no escaping the reality [that these measures] will cause severe disruption across the country for many months. But it will help slow disease and save lives."