The chairman of the British Medical Association, Dr Chaand Nagpaul, said it "makes no sense" to stop wearing face masks in enclosed public settings amid a rising number of cases of the Delta variant.
He told BBC Radio 4's Today programme "face masks are proven to reduce spread of this infection" and "we can't understand why we would knowingly want people to become infected".
Unions representing public transport and shop workers said their staff would face even more risk of infection if face mask rules are dropped.
Meanwhile, Ryanair said face masks would remain mandatory on its flight "in order to protect the health of our passengers and crew".