Ministers urged to end face coverings confusion.
The government has been accused of mixed messaging over where people will have to wear face coverings when new rules come into force.
They will be compulsory in shops in England from Friday – but full guidance is yet to be published.
Trade bodies and opposition MPs said confusion remained over takeaways.
Minister Brandon Lewis said face coverings would be mandatory when purchasing takeaway food and drink, but not if you are eating at the premises.
“If you are going into a takeaway and you are eating in somewhere that’s got a takeaway, then that is like hospitality. You are eating – it’s not practical to wear a face mask, we recognise that,” the Northern Ireland Secretary said.
“But if you are going in to buy a product and leaving again, then you are treating it like a shop and you should be wearing a face mask.”
A Department of Health spokesman said: “If a shop or supermarket has a cafe or a seating area to eat and drink, you can remove your face covering in that area.”
However, Kate Nicholls, chief executive of UK Hospitality, said this contradicted what the industry had previously been told by the government and it was “very late in the day” for this to be confirmed.
“It’s really unhelpful to have that confusion because the single biggest thing we need now is to rebuild consumer confidence and that needs clear, unambiguous messaging,” she told BBC Breakfast.
The new regulations will only be published on Thursday, less than 24 hours before they come into effect.
The criticism came after Mr Hancock and Boris Johnson’s official spokesman contradicted each other over the rules on takeaways and sandwich shops.
The health secretary said last week: “You do need to wear a face mask in Pret because Pret is a shop. If there’s table service, it is not necessary to have a mask. But in any shop, you do need a mask. So, if you’re going up to the counter in Pret to buy takeaway that is a shop.”
But the prime minister’s spokesman later said: “We will be publishing the full guidance shortly but my understanding is that it wouldn’t be mandatory if you went in, for example, to a sandwich shop in order to get a takeaway to wear a face covering.”
Face coverings have been compulsory in shops in Scotland since 10 July. Shoppers are not currently required to wear them in Wales or Northern Ireland, although this is being considered.
Health Secretary Matt Hancock announced on 14 July that wearing a face covering in shops and supermarkets would be compulsory from Friday, 24 July, with anyone failing to comply facing a fine of up to £100.
The same exemptions as for public transport will apply, with children under 11 and people with breathing problems not required to wear a covering.
Anyone who cannot put on, wear or remove a face covering because of a physical or mental illness or impairment or disability is also exempt.
Can police make me cover my face?
The Police Federation, which represents front-line officers, says they can’t spend their time patrolling thousands upon thousands of outlets.
Shop staff and security guards can already detain shoplifters while waiting for the police to arrive. However, the general power of the citizen’s arrest is only exercisable to apprehend criminals committing offences that would go before a judge and jury. A penalty ticket for being socially obnoxious would not cross that high bar.
Police leaders hope shop managers will refuse non-mask wearers entry – rather than turning to the police to solve the problem.
Met Commissioner Dame Cressida Dick has said that police in London would only enforce the wearing of coverings in shops “as a last resort” – if people not wearing a covering refused to leave a shop or became “aggressive”.
Liberal Democrat health spokesperson Munira Wilson called for urgent clarity for businesses and to help people feel safe.
“Clear communication is critical in a public health crisis. Instead, this confusion on guidance shows ministers simply could not organise a bun fight in a bakery,” she told the PA news agency.
“All this stinks of ministers making it up as they go along instead of listening to the experts.”
Tracy Cannard, who works in a supermarket and is a representative of the shopworkers’ union USDAW, said while increasing numbers of customers were choosing to wear masks this still only amounted to around 20% and making it compulsory would help her feel safer.
Face coverings are already compulsory on public transport in England and Scotland, as well as most buses, trains and ferries in Northern Ireland.
They will be mandatory on public transport in Wales from 27 July.