It would cost delinquent motorists in the District $50 rather than the current $25 to have the much-dreaded "boot" removed from their cars under legislation proposed by Mayor Marion Barry and being considered by the City Council.

At a hearing of the council's Public Works Committee yesterday, a Barry administration official said the increase is needed to end a deficit in the booting program. Boots are immobilizing devices attached to the cars of motorists who are delinquent in paying parking fines.

The committee's reaction to the proposed increase in fees was mixed, and the administration was asked to bring back more information on the idea and its impact.

"I don't know how this bill will go," said council member Nadine P. Winter (D-Ward 6), committee chairwoman, adding that she wanted the administration to look at how booting policy affects parking regulation enforcement. "This bill came about because people were concerned about people just parking and parking and nothing being done about it," she said.

Robert O.D. Thompson, D.C. Department of Public Works transportation system administrator, said operating costs of the program in this fiscal year are projected at $932,000, but revenue is expected to be only $475,000.

In fiscal 1985, the District booted 20,795 cars, of which 37 percent had Maryland registrations, 26 percent had Virginia registrations and 18 percent had District registrations.

The law allows the city to boot a car if the owner has two or more outstanding parking or traffic tickets, but in practice the city boots only after a driver has four unpaid tickets, Thompson said.

The boot removal fee must be paid in addition to the all outstanding fines. Thompson said the booting program has increased payment of tickets from less than 50 percent in 1979 to 70 percent now.

Council member Frank Smith (D-Ward 1) said he was not necessarily opposed to raising the fee, but that booting after three rather than four tickets might be another way to raise revenue for the program.

"I think the public is getting the feeling that we are taking advantage of them with this program," Smith said. "I have some sensitivity to the public view that this is a nuisance and that this is a way of giving them a back-door tax increase."