D.C. Mayor Marion Barry plans to ask the City Council to enact urgent legislation restoring the power of city police to enforce traffic regulations that were weakened by a loophole in the District of Columbia's new administrative enforcement program, Barry's top aide disclosed last night.

City Administrator Elijah B. Rogers announced the decision after Barry summoned key legal, police and transportation officials to his office to map ways to prevent a disruption in traffic law enforcement.

Barry acted one day after D.C. police issued new guidelines instructing officers on their curtailed authority under the new traffic program, which shifts the enforcement of all but a few serious violations from the courts to administrative tribunals, Corporation Counsel Judith W. Rogers recommended that the mayor ask for prompt council action rather than issuing an executive order, which Elijah Rogers said would be of questionable legality.

The council is scheduled to meet next Tuesday. It could invoke emergency power to enact the measure immediately to take effect as soon as it is signed by the mayor. Council leaders could not be reached last night for comment on the mayor's proposal.

Among other provisions, the proposed legislation would restore the clear power of the police to require motorists to obey their orders, including orders to stop for the discussion and investigation of possible violations, and to show their driver permits and car registrations when asked. That authority lapsed Monday.

Despite the lapse, which cast doubt on the legality of such police powers under some situations, Barry told a news conference earlier yesterday that motorists will continue to be arrested if they refuse to stop on a police officer's order after committing an apparent traffic violation.

"You can't do that," Barry said. "They [the police] will arrest you and stop you . . . So don't go out and do that, because you will wind up in the central cellblock."

The flap over police powers stems directly from apparent loopholes found in an administrative order issued two weeks ago by the city's new director of transportation, Thomas Downs. The order put into effect rules proposed nearly two years ago by his predecessor to carry out a council-passed law removing the criminal stigma from most traffic offenses.

Elijah Rogers said last night that "the rules were published prematurely," but he refused to pinpoint blame.

Downs himself said he already had agreed with the police department and the corporation counsel's office that legislation should be introduced to cure the flaws in the new rules.

Under the program, all but a relatively few serious traffic offenses are now considered to be administrative rather than criminal violations of law. Motorists cited under the administrative provisions would either forfeit collateral or appear for adjudication of their violations before a civilian hearing officer rather than a judge. The hearing officers are the same ones who have dealt with parking violations for the last two years.

Motorists accused of the lesser violations, such as running a stop sign or speeding a few miles over the limit, would be cited to appear later but no longer are subject to arrest, unless police consider the infractions to constitute reckless driving. Those accused of more serious criminal offenses, such as reckless or drunken driving, still could be arrested.

Lawyers for the police department, studying the proposed rules before they went into effect, discovered that the new rules -- apparently by oversight -- knocked out the right of police to require motorists to obey their orders or to require them to produce their drivers' licenses or car registrations.

"You cannot issue a citation until you know who you are going to issue it to," police lawyer Richard Brooks observed.

The new rules also omitted giving police the power to require jaywalkers and other pedestrians accused of violations to give their correct identities, and the power to enforce rules that prohibit parades without permits.

Other violations that still are subject to criminal charges include leaving the scene of an accident, driving more than 30 miles per hour over the posted speed limit, driving an unregistered vehicle, driving an uninsured taxicab and driving without a valid permit.

Administrative judging of lesser traffic violations is done now in New York state and Rhode Island and is being considered by at least a half-dozen other states, according to Robert Andretta, D.C.'s chief traffic hearing officer.