Mayor Bill de Blasio on Tuesday warned that the city is on the verge of an unprecedented “shelter-in-place” order to contain the coronavirus — saying he expects as many as 10,000 cases of the contagion in the Big Apple by next week.

“New Yorkers should be prepared right now for the possibility of a shelter-in-place order,” the mayor said at an afternoon press conference, noting that the current number of confirmed cases of the virus in the city has soared to 814 — with seven deaths.

“It has not happened yet, but it is definitely a possibility at this point,” the mayor said of an order that would keep most New Yorkers off the streets for most of the time.

Earlier in the day, de Blasio talked about a situation similar to San Francisco, where residents would only be allowed out for food and pharmacy shopping, as well as exercise.

“I believe this decision should be made in the next 48 hours,” the mayor said of a New York City order.

“We’ve never been here before. I have never heard of anything like this in the history of New York City. Never anything close to this,” admitted the mayor — who has been roundly criticized for not taking steps sooner to mitigate the virus’ spread, including waiting to close the city’s public schools till Sunday.

“We’re certainly going to have thousands of cases next week,” he said of the contagion. “It’s not that long until we hit 10,000 cases. That’s a true statement, whether it’s next week or some later period. That’s not that far off.”

De Blasio said the city will be launching a “wartime mobilization” effort to recruit more health-care workers to help with the crisis.

He said the city does not have enough equipment and supplies for “the long haul” — and it is “even more challenging” to get adequate personnel.

In launching a citywide campaign to gather more medical workers, “It will look and feel like a wartime mobilization message,” Hizzoner said.

“If you are a healthcare worker, or if you have appropriate training, we need you, and we need you right away,” he said.

“This is so far from business as usual, there are no words.

“Anyone who can bring health care to the equation, your city needs you now.”

-Additional reporting by Jorge Fitz-Gibbon