A massive undertaking to transform the Boston Convention center’s cavernous showroom floor into a temporary hospital for coronavirus patients in just four days got underway this weekend and could have the space ready as early as this week, Boston Mayor Martin Walsh said Sunday.

“We don’t need it today, but as you can see the numbers surging. As these numbers surge there will be a need for additional beds, and that’s what will activate the convention center,” Walsh said at a press conference Sunday in front of city hall.

Workers from trade unions and other organizations donned gloves and face masks on Sunday and erected white temporary walls, creating hundreds of cubicles that will house patients should the coronavirus pandemic overwhelm Boston’s hospitals.

When the build out is done later this week, the Boston Convention & Exhibition Center will host 1,000 beds, increasing capacity to treat coronavirus patients. Of those, 500 will be for homeless individuals and another 500 will be for noncritical patients who’d otherwise need to be in the hospital. There will also be six acute-care suites and a physical therapy suite as well as 52 nurses stations and 48 bathroom facilities.

More than 1,000 people have already been hospitalized from COVID-19 in Massachusetts and field hospitals like the one at the BCEC  will help free up space inside intensive-care units for the most critically ill patients.

“We’re preparing for whatever comes our way for our vulnerable residents and for all of our residents. But what we don’t want is to have to test the limits of this new medical capacity,” Walsh told reporters, introducing a set of stricter stay-at-home measures and urging all residents to wear masks whenever they go out in public.

The BCEC is one of several sites being transformed into field hospitals as the state braces for a surge in coronavirus patients. The latest modeling shows up to 172,000 Massachusetts residents could contract COVID-19.

The surge is expected to strike between April 10 and 20, Baker said.

Temporary hospitals are being built at Worcester’s DCU Center with UMass Medical and at the Joint Base Cape Cod in cooperation with Cape Cod Hospital. The three sites will increase the Bay State’s hospital capacity by 1,500 to 2,000 beds, Gov. Charlie Baker said Sunday speaking at Gillette Stadium in Foxboro where a drive-thru testing site for front-line responders was opened.

Baker said “a number” of other sites are also being considered. Several hospitals — including Morton Hospital in Taunton — as well as some skilled nursing facilities are being converted to coronavirus treatment centers.

These COVID-19 field hospitals will be staffed by health care professionals as well as volunteer health care workers most of whom are coming out of retirement.

“We have lots and lots of people who are very mission-driven, who are responding to a call in this particular circumstance and situation, and want to be there for their neighbors, friends and colleagues,” Baker said.