Parking Management Inc. (PMI), the city's largest parking operation, has been parking cars on city-owned property in downtown Washington for at least three years without permission and without paying any rent to the city for the use of the land.

PMI's use of the city property next to PMI's lot at Third and E streets NW has gone undetected until recently, according to city officials. PMI had blacktopped both its own lot and the adjacent city land and had painted connecting parking lane stripes on the combined space. One official estimated that a fair rental charge for use of the city land - which has space for about 70 cars, about a third of the total PMI lot - might be as much as $37,000 a year. Another city official said the government will try to collect back rent from PMI.

PMI's president and principal owner is multimillionaire parking executive and developer Dominic F. Anotonelli Jr. Neither he nor any PMI official returned a reporter's telephone queries about the lot's use.

"It's a case where somebody, just an interloper, was using the District property without paying," said Douglas Schneider, director of the D.C. Department of Transportation.

Schneider said he plans "soon" to determine the fair market lease on the about 10,500 square feet of D.C. land involved and to "press" for payment by PMI "if the corporation counsel lawyers can make out a case."

Schneider said the PMI matter came to his attention about four weeks ago and was referred to the city's Department of General Services. DGS director Sam Starobin then decided to separate the city property from the rest of the PMI lot with barricades. The red and white wooden barricades were set in place a week ago Monday.

Earlier, city surveyors were chased off the PMI lot when they came to establish the correct property boundaries, according to one official. Don Croll, chief of the DGS real estate acquisition division, said yesterday the surveyor group "was, in effect, chased off District property" when it tried to survey the area and check property lines.

When PMI continued parking car on the city's land, Croll said, he called in D.C. police to ticket the illegally parked cars.

However, Croll said he "backed off" ticketing the cars after deciding such action "would unfairly penalize innocent people" whose cars were parked on city property without their knowledge. Instead, police stood by while the lot's attendants started moving the cars to legal spaces.

Croll said he first visited the PMI site on April 12 and was told by the lot manager to contact PMI's main headquarters about any problems. The next day, Croll said, he sent a hand delivered letter to Antonelli threatening to ticket or tow any cars found parked on city land.

On April 14, the day the police were to begin ticketing, Croll said he and Antonelli discussed the situation by telephone. "He wanted us to hold off enforcing it (the parking ban) until he could block it off himself," Croll said. But I warned him the police were coming that day to ticket.

On the Saturday following Croll's conversation with him, Antonelli had concrete wheel stops placed along his lot's property line to separate it from city land, according to Croll.

According to Croll, Antonelli also offered to begin leasing the additional parking space from the city. "He wanted to negotiate a lease right then, but we told him that under the circumstances we thought competitive bidding was in order," said Croll.

"Mr. Antonelli was hardly cool, calm and collected" during the conversation, Croll recalled. "He asked us why we were just now enforcing this. But I told him, 'You can talk about this all you want to but the fact remains your're using D.C. property and you have no right to'"

Croll's conversation with Antonelli took place the day after Antonelli and mayoral aide Joseph P. Yeldell were arraigned in U.S. District Court here on charges of bribery and conspiracy in the awarding of a controversial city lease on an Antonelli owned building. Trail has been set for Sept. 18.

According to both Schneider and Croll the city land in question is part of surplus property the District purchased during construction of the Center Leg Freeway from the Southwest Freeway to New York Avenue N.E. Most of the property lies adjacent to the freeway wall.

In 1966 the District government and an Antonelli real estate partnership swapped property in that same block in preparation for the freeways' construction. Because the land Antonelli exchanged with the city was more valuable than what was traded to him, the District paid his firm an additional $309,500.

Schneider said there have been in stances of other unauthorized use of unimproved city land "but not on so large a scale as this or quite so blatant where they go in and pave it over and stripe it."

Bids on year long lease of the property will be opened in mid-May, but the city hopes to sell the property in another year.

Schneider said his agency is not yet certain of how long PMI has used the city land. He said the highway contractor left the area in November 1974 and the city government has an aerial photo dated May 1975, which shows the property paved and striped.

PMI charges $2.85 a day to park in the lot, including 31 cents in city tax. The monthly parking cost is $45.

The lot also has a special red coinbox that is identified by a sign as a device for "honor system parking." The sign asks parkers to voluntarily pay 50 cents to the coinbox after closing or whenever the lot is unattended.

Antonelli, 55, has been an important parking lot and development figure in Washington for more than 30 years. He owns scores of lots and garages in the city, most of them located in or near buildings he owns or has helped develop.

Antonelli's real estate holdings include numerous properties in the old downtown and in the newer sections west of 16th Street NW. He also owns properties in Maryland and Virginia as well as in other areas of the country. In 1975, he estimated his own personal net worth to be $30 million.