The District of Columbia government has discovered that its own employes have piled up perhaps as many as 1,000 unpaid parking tickets while driving around town in about 400 city owned cars and trucks.

The ticket problem "indicates a mistaken belief on the part of some District employes that they are exempt from parking regulations while on official business," city administrator Julian R. Dugas said in a memorandum distributed last week to heads of city departments and agencies.

City law enforcement officials want the tickets paid by the responsible employes, but, they said, nobody knows who was driving what vehicle when.

"Nobody keeps that kind of record, unfortunately," said Douglas N. Schnelder Jr, director of the city's Department of Transportation.

In the meantime, the city police department has threatened to refuse to issue new 1979 registrations to the 400 delinquent vehicles because of the unpaid tickets, officials said. The registration deadline is Friday.

In his memorandum, Dugas said he has requested that Police Chief Burtell Jefferson and Schneider see to it that the vehicles are registered, despite the unpaid tickets.

But from now on, Dugas said in the memo, city departments and agencies will be required to keep strict logs on their employes' use of city owned vehicles.

District of Columbia residents who own vehicles are denied renewed license tags at registration time until all outstanding traffic tickets are paid, according to the city Police Departments's traffic and criminal warrants section.

It was not until this year that the city's computer was programmed to account for government vehicles with unpaid parking tickets said Robert O.D. Thompson, assitant director of the city's Bureau of Motor Vehicle Services.

The result, Thompson said, was a 10-page computer print-out that listed close to 400 city owned vehicles, from sedans to pick-up trucks with unpaid, parking tickets accumulated over the past three to four years.

In the past, traffic officials notified the heads of city departments and agencies about outstanding tickets, he said. These supervisors then tried to locate the responsible employe and collect the fines. Some money was paid, but some offenders slipped through, Thompson said and registration was not denied.

The administrative cost of trying to figure out which employes were responsible for which tickets "would be enormous," Scheneider said in a telephone interview. If the departments or agencies themselves were required to pay the fines, they would have to get an appropriation of funds that would amount, in effect to "the citypaying itself," he said.

So, Dugas said in the memorandun, he has requested Schneider and Chief Jefferson to allow the delinquent vehicles to be re-registered.

However, from now on, Dugas said, each department and agency will be required to keep a daily journal of employe assigments to vehicles and employes will be told that they are responsible for all tickets issued to vehicles they use. [LINE ILLEGIBLE]

Any request for cancellation of traffic tickets by a District of Columbia employe must be in writing and is subject to final approval by the Law Enforcement Section of the criminal division of the corporation counsel's office.

Employes often make such requests when a ticket is issued during official business or during an emergency.

The corporation counsel's office begana crackdown on cancelation of tickets for city employees last September.

"The message that has to come out is that we are treating traffic tickets in a very serious way, no matter who gets them," said Geoffrey M. Alprin, deputy corporation counsel in the criminal division.