New York City will soon require proof of Covid-19 vaccinations for anyone who wants to dine indoors at a restaurant, see a performance or go to the gym.

The announcement today by Mayor Bill de Blasio makes New York the first big city in the US to impose such restrictions.

The new requirement, which will be phased in over several weeks in August and September, is the most aggressive step the city has taken yet to curb a surge in cases caused by the Delta variant.

People will have to show proof that they have had at least one dose of a vaccine.

“The only way to patronize these establishments indoors will be if you’re vaccinated,” Mr de Blasio said.

“The goal here is to convince everyone that this is the time. If we’re going to stop the Delta variant, the time is now. And that means getting vaccinated right now.”

The Democrat said some details still need to be worked out, including rules affecting children under 12, who are not yet eligible for any of the approved vaccines.

The policy will go into effect on August 16 but inspections and enforcement won't begin until September 13, the week that the city's public schools reopen for the autumn.

Vaccination cards will be accepted as proof of inoculation, along with state and city apps.

Mr De Blasio has focused on getting as many New Yorkers vaccinated as possible while resisting calls to make it mandatory for masks to be worn indoors, as several cities and counties in California have done.

Mr De Blasio said yesterday that he was making “a strong recommendation” that everyone wear a mask in public indoor settings, but stressed that the city’s “overwhelming strategic thrust” remained getting more people vaccinated.

Asked today about a mask mandate, he said all options were on the table but reiterated that the city's policy is “vaccine-centric”.

“Right now what we want to nail is people getting vaccinated, and, very bluntly, showing that life is much better when you’re vaccinated," he added.

“You can do so much more when you’re vaccinated. You have more freedom when you’re vaccinated, and you have a lot less, you have fewer choices, fewer opportunities if you're not vaccinated.”

He announced last week that city employees would be required to get vaccinated by mid-September or face weekly testing, and he has offered a $100 incentive for city residents who get inoculated.

Mr De Blasio said today that he did not think checking customers’ vaccination status should be too difficult for businesses, which already have to take tickets or show diners to a table.

Major performance venues including Broadway theatres and the Metropolitan Opera have already announced that vaccinations will be required for audience members.

About 66pc of adults in New York City are fully vaccinated, according to official data.