The Ku Klux Klan's announced plan to hold a march and rally in Washington on Nov. 6 may have been preempted by four anti-Klan groups that have applied for permits for that date, the National Park Service said yesterday.

Since the Klan's Sept. 8 announcement, the four groups have applied for permits covering at least 15 major sites in the city for Nov. 6 -- four days after the national and local elections -- including the Washington Monument and Lafayette Square, two likely sites mentioned by the Klan. The Klan has not filed an application, as required, with the Park Service.

"If the Klan applies for the same date, it looks like these other groups have tied up all the park areas already," said Sandra Alley, a Park Service representative, who said permits are issued on a first come, first served basis.

Alley said it is unlikely that the Park Service would allow the Klan and anti-Klan groups to demonstrate in the same areas. "It's like what we went through with all the Iranians, the pro-Shahs and anti-Shahs," she said. "We will not put them in the same area" because of the possibility of violence.

If the Klan applies, Alley said, the Park Service will determine whether other sites are available for a demonstration and whether the Klan's plans would present a "clear and present danger to the community," in which case the permit would be denied.

The anti-Klan groups, which said their rallies are in support of "human dignity" and against the Klan and racism, are the Metropolitan Washington Anti-Klan Network, the All Peoples Congress, the Peoples Antiwar Mobilization, and the John Brown Anti-Klan Committee.

"As far as I know, we are still planning to march," Stanley McCollum, director of the national office of the Knights of the Ku Klux Klan, said in a telephone interview yesterday from his office in Tuscumbia, Ala.

McCollum said the Klan's permit application was delayed because a Washington-area Klan member, whom he would not identify, had apparently not gotten around to applying for the permit.

If the Klan marches here, it would be the first major Klan demonstration in Washington since 1926. Plans for the march developed early this month at a meeting of seven Klan groups in Stone Mountain, Ga.

McCollum said the post-election demonstration is aimed at publicizing the Klan's opposition to affirmative action programs and other government actions.