Health Secretary Matt Hancock said shop workers should call the police if customers refuse to wear a face mask.
Mr Hancock told the Commons face coverings can help to protect shop assistants and restore the confidence of shoppers.
However, he said those who do not have a valid reason not to wear a face mask should be expelled from shops.
He told MPs: “Just as with public transport, children under 11 and those with certain disabilities will be exempt. The liability for wearing a face covering lies with the individual.
"Should an individual without an exemption refuse to wear a face covering, a shop can refuse them entry and can call the police if people refuse to comply.
"The police have formal enforcement powers and can issue a fine."
It comes after the Government ended days of confusion on face masks yesterday, with Boris Johnson signalling they would be mandatory in stores from July 24.
However, the delay was slammed by the British Medical Association, the head of JD Sports, scientific experts and London Mayor Sadiq Khan.
Mr Hancock added: “Sadly sales assistants, cashiers and security guards have suffered disproportionately in this crisis.
“The death rate of sales and retail assistants is 75 per cent higher amongst men and 60 per cent higher amongst women than in the general population."
