A life science and tech campus including the future General Electric headquarters in Boston could reach 650,000 square feet, the new owners of the property said.

Alexandria Real Estate Equities and National Development are preparing to break ground in early 2020 on a 330,000- to 360,000-square-foot office and lab building on the property formerly envisioned for GE’s signature headquarters building, Alexandria executives said Tuesday in a conference call on the company’s second-quarter earnings. A 293,000-square-foot office tower was previously approved for GE’s headquarters.

“The existing approvals that reside there will enable us to expedite the entitlements and likely put us in a position to break ground in early 2020,” Alexandria co-CEO Peter Moglia said on the call.

Along with the 1-acre former GE development site, the campus will include two renovated warehouses with 75,000 square feet of office space leased to GE and the Necco Street garage, which could be expanded with office and lab space. The garage site could add approximately 175,000 square feet of commercial space, according to Alexandria’s financial statements.

General Electric began renovations at the 95,400-square-foot warehouse buildings in December 2017, but delayed and ultimately opted not to build the new office tower next door in a cost-cutting measure. MassDevelopment had previously bought the warehouse properties for $57.4 million, while GE paid $25.6 million for the parking lot where the office tower is planned.

After GE scaled back its Boston expansion and job growth targets, it agreed to jointly market the two parcels with MassDevelopment. Alexandria and National Development paid $252 million for the properties in May.