Roman Catholic Archbishop James A. Hickey of Washington, breaking his long silence on the Nov. 3 educational tax credit referendum in the District of Columbia, yesterday said Catholic parents should make up their own minds how to vote on the initiative, but took no position of his own.

In a written statement, Hickey did not elaborate on his reasons for not taking any stand on the initiative, a concept that the Roman Catholic hierarchy has supported and made a top priority elsewhere.

Numerous other religious groups and all of the city's top elected leaders have voiced their opposition to the tax credit proposal. A spokesman for the National Taxpayers Union, the strongest supporter of the initiative, said that no religious organizations in the District support the initiative, although a number of individual church leaders, including the lay president of the archdiocesan school board, Terrence Scanlan, are working actively for its passage.

The initiative, if approved, would permit taxpayers to reduce their D.C. income taxes by up to $1,200 per pupil for expenses they incur at either private or public schools. It has been sponsored by a local offshoot of the taxpayers group.

"I am concerned for the children in all our schools," Hickey said in the statement. "The public schools serve the majority of our Catholic students from the District. The parochial and private schools permit parents to have religious faith and moral values integrated with the education program of their children.

"While the proposed law was not initiated, formulated nor sponsored by the Archdiocese of Washington," Hickey said, "I strongly support the right of parents to make decisions with regard to the education of their children. The voters of the District of Columbia must decide whether or not the proposed initiative best serves that purpose."

Hickey could not be reached for further comment.

Phyllis Frank, speaking for the D.C. Coalition Against Tuition Tax Credits expressed appreciation for Hickey's neutrality, but indicated that she felt voter education is more important than the positions of individuals. "We want the people to know, especially the people in Ward 3, that their property taxes are going to go up if this thing passes," said Frank, national public relations director of the American Federation of Teachers.

Speculating that citizens will vote their pocketbooks on the issue, she declined to predict the outcome. "In all the years I've lived here, I don't think I've ever seen such a broad spectrum of groups and people united on an issue in opposition to the tax credit proposal . But whether we can get our message across, it's hard to know," she said.

Last week the predominantly black Baptist Convention of the District of Columbia, which includes 77 congregations in the District, unanimously adopted a resolution opposing the education tax credit initiative. The Rev. Jerry A. Moore Jr., president of the convention and also an at-large city councilman, said the tax credit "would benefit upper-class people and deprive lower-income residents" and would force an increase in property taxes to maintain support of public schools.

Both the predominantly Protestant Council of Churches of Greater Washington and the Jewish Community Council are members of the coalition of community groups fighting the tax credit initiative.

Charles M. Pike Jr., campaign manager for the D.C. Committee for Improved Education, the NTU offshoot working for passage of the initiative, said he was not surprised by Hickey's neutral stance. "As a Catholic, it's been my experience that the church hierarchy rarely gets involved in political issues. The Catholic Church, probably more than most churches, tends to stand back from political issues," he said.

Actually, the U.S. Catholic Conference, the action arm of the hierarchy in this country, employs full-time lobbyists to press for legislation reflecting the church's position on such issues as abortion and aid to parochial schools. Only last month the conference's education office urged diocesan school leaders throughout the country to organize letter-writing campaigns to try to persuade Congress to support tuition-credit legislation on the national level.

According to archdiocesan school figures, 9,183 children who are residents of the District are enrolled in Catholic schools here. The number of Catholic children in D.C. public schools is not known. A spokesman for the Catholic schools office said that tuition in Catholic schools here ranges from around $600 a year for elementary pupils to $1,200 to $1,500 for secondary schools