Ten U.S. Park Police officers trooped into the Capitol Hill office of Rep. Stan Parris (R-Va.) yesterday to protest what they charged is an inadequate effort by park police to halt drug trafficking in federal parks in the Washington area.

The officers, mostly union representatives, told Parris' aides that the Park Service has sought to play down the extent of the drug problem, abolishing or decimating special units set up to make a concerted attack on it and reducing the overall number of officers in the Washington area.

"It the trafficking is open, and you're so short of manpower, it's hard for two officers to make an arrest in a crowd of 100 people. It's dangerous," one of the officers, who asked not to be named, told a reporter. He said there is widespread drug dealing in the parks, leading to rapes, assaults, and deaths from drug overdoses.

"We are the only department in the area that doesn't have a vice squad," another officer said. "The Reagan administration is fighting drugs all over except in front of its nose."

James C. Lindsey, deputy chief commander of the park police operations division, acknowledged yesterday that the number of officers has declined because of budget cuts, but said the police effort to attack the drug problem has not been diminished.

Lindsey, asserting there is no need for a vice squad, said many of the same functions can be handled by officers on patrol. "If somebody has said don't lock somebody up, I want to hear about it," he said.

"The drug problems in federal parks are no different from the rest of the community . . . . The officers are constantly making arrests," Lindsey said. "You're dealing with perceptions. What is a big drug problem in the park? It's a question of priorities and resources."

Several of the protesting officers told a reporter yesterday that they decided to go to the congressman after two park police officers were injured Thursday while investigating a complaint that a man was selling drugs to visiting South Carolina schoolchildren on the Washington Monument Grounds. The man, Kenneth Vines, 19, of Baltimore, died after an exchange of gunfire with the officers.

"We thought we would get a better response from the Hill" than by taking the complaint through channels, said one of the protesting officers, who asked not to be named.

In particular, the officers told a Parris aide that parks along the George Washington Memorial Parkway, Meridian Hill Park, Franklin Park, Anacostia Park, East and West Potomac parks, and Rock Creek Park are areas where there are drug transactions and addicts openly shoot up heroin, cocaine and other drugs.

Last year, one of the officers said, park police investigated 1,653 incidents involving drugs in the Washington area. Figures for the previous year were not immediately available.

In February, a park police task force on narcotics was abolished after it had made several arrests of drug dealers, according to one of the protesting officers. Over the past three years, he said, the number of officers has been cut by 58 positions to 410 officers.

Another officer said a tactical unit of up to 10 officers last year made as many as 133 arrests in Franklin Park at 14th and I streets NW, a one-square-block area. Now, there are only five such officers assigned to the unit, and arrests in the park have dropped, he said, adding, "If you need saturation, we don't have it."

"They want you to make an arrest when you see a crime. When you actively look for the crimes, then you raise the statistics, which they don't like," he said.

Parris, a member of the Select Committee on Narcotics and Drug Abuse, asked yesterday for a meeting with Interior Secretary James G. Watt to discuss the charges. The meeting is to take place this week, he said.