A plan to sell the Hynes Convention Center off to the highest bidder with little thought as to what might replace it would be akin to conducting “open-heart surgery” on the Back Bay, City Councilor Kenzie Bok told lawmakers on Monday.

“You’re trying to conduct open-heart surgery with really no community process at all,” Bok said during a hearing of the Joint Committee on State Administration and Regulatory Oversight at the State House.

Legislators must approve a bill before the Massachusetts Convention Center Authority can sell off the property, but Back Bay residents and business owners asked lawmakers to pump the brakes on a process they say they feel shut out of.

The sale of the John B. Hynes Veterans Memorial Convention Center is intended to fund an estimated $500 million expansion of the Boston Convention & Exhibition Center — a move MCCA Executive Director David Gibbons says is necessary to stay competitive.

The deal also includes transferring 12 acres of land in South Boston near the BCEC back to city ownership. City officials have so far been tight-lipped on what their plans are for the land.

The South Boston delegation is on board with the project that they said would create 1,200 permanent jobs. Design and construction would take about 36 months, according to Gibbons.

Their counterparts representing the Back Bay said they would back the BCEC expansion, but asked for a new bill “de-coupling” the fates of the two convention centers. MCCA officials spent two years meticulously planning the expansion of the city’s 16-year-old flagship convention center in the Seaport, but Rep. Jon Santiago said the Hynes redevelopment has not been thought out.

“Livelihoods are at stake. The service industry and the microeconomy of the Back Bay hangs on the Hynes,” Santiago said, noting no economic impact study has been completed.

Bok said approving the sale of the Hynes prior to community discussions about the site’s redevelopment is an “example of the kind of short-sighted decision making that we need to step back from.”

Eileen Williston, managing director of Boston Lyric Opera said the location is perfect for a performing arts center.

“We have the opportunity to create an iconic landmark that is a space of innovation and access, serving and engaging its neighborhood, its city, and its region, with daytime and evening activities year-round,” she said.

Gibbons said selling off the 52-year-old “aged, land-locked” Hynes Convention Center, which he said needs at least $200 million in repairs, has the “opportunity to be transformational” to the Back Bay neighborhood.

Gibbons declined to say how much he thinks the of the Hynes property on Boylston would sell for, but said the price tag would likely not be enough to cover the full cost of the BCEC expansion.

“Selling the Hynes will generate the highest return with the lowest risk to taxpayers,” Deputy MCCA Director Dennis Callahan said.