The decision by Long Island College Hospital to close its obstetrics unit will deprive Brooklyn residents of needed maternity services, according to elected officials who plan to rally outside the hospital today.

Last week, the cash-strapped hospital, situated in Cobble Hill, announced its intention to close the maternity unit as part of a reorganization plan that also includes downsizing its number of beds and selling off parcels of real estate.

“There’s been a bigger pattern in Brooklyn in recent years of hospitals closing maternity wards or closing altogether, which really has reduced the availability of maternity services,” a City Council member of Brooklyn, Bill de Blasio, said. He said he plans to ask the state’s Department of Health to analyze the hospital’s proposal and “tell us whether our community can survive this move.”

Mr. de Blasio said he would like to see a clear financial plan for the hospital’s future to quell concerns and rumors that the hospital is planning to close altogether, a claim the hospital denies.

The hospital, part of the Continuum Health Partners network, owes $170 million to creditors. Hospital officials said the obstetrics department accounts for 33%, or $11 million, of the hospital’s annual losses and racks up $8.8 million each year in medical malpractice costs, an amount that represents 40% of the hospital’s total malpractice costs.

Hospital leaders said the plan was designed to avoid bankruptcy. But the hospital’s medical staff has alleged that its parent company, Continuum, mismanaged Long Island College Hospital, investing in its other hospitals, Beth Israel Medical Center and St. Luke’s-Roosevelt Hospital Center, both in Manhattan.

A spokesman for Continuum, Jim Mandler, categorically denied that Continuum siphoned off money to support other hospitals. “In every meeting we have tried to underscore the fact that it’s simply not true, that it would be an illegal practice to do that and that our plans for restructuring is a plan to save the hospital,” he said.