The Vatican for the first time yesterday called upon Catholics around the world to put pressure on their governments to provide public aide for parochial schools and warned against allowing Catholic schooling to become education for the rich.

In a 10,000-word document, the Sacred Congregation for Catholic Education expressed support for teachers', unions in Catholic schools, urged priests, brothers and nuns not to abandon teaching and insisted that the church's schools must meet high professional standards.

With the exception of the union issue - currently a hotly debated item in the American Catholic church - the Vatican statement "affirms what has for a long time been the policy" of American bishops, according to a U.S. Catholic Conference spokesman.

Russell Shaw, the spokesman, speculated that the statement would have little impact on U.S. Catholic efforts to obtain federal and state school aid and merely "gives a word of encouragement" to lobbying efforts espoused by the American church hierachy in recent decades.

Ed Doerr of Americans United for Separation of Church and State, which was founded after World War II in part because of the parochial school aid issue, discounted the Vatican statement as merely making "explicit a policy which has been implicit for a great long time" in the United States.

Robert O'Dean, who coordinates the inpact Protestant lobby under the auspices of the National Council of Churches in Washington, said, "I don't anticipate any changes in relationships between Catholics and Protestants over this."

In the United States, Catholic Conference spokesman Shaw noted, "the problem as we see it is not so much legislative" but the Supreme Court's interpretation of what public aid is constitutionally acceptable.

Currently the greatest push for Catholic school aid is at the state level, he added. Lobbying in Congress is "in a kind of holding pattern" until the Supreme Court resolves the issue, he said.

The high court has wrestled with the basic theme since 1947 when Catholic-Protestant relations were at a low point over public aid to parochial schools and American representation at the Vatican.

Since then, the court has struck down numerous state law enacted to assist Catholic schools and has dimmed Catholic hopes of obtaining substantial public aid.

In a decision two weeks ago, the court reaffirmed its position that states can provide textbooks to parochial school pupils, but said the First Amendment barrier between church and state forbids the supply of other instructional materials, instructional equipment and field-trip transportation.

The Vatican document pointed out that Catholic schools in some countries serves only the rich, and it attributed this to the state's failure to appreciate the benefits of a Catholic school system and to support it financially.

Italy, Spain and West Germany are among countries that subsidize Catholic schools, usually on a per-pupil basis.

Almost 30 million children attend primary and secondary Catholic schools in the world, according to Vatican statistics. The American Catholic school enrollment was 3.4 million in 1976, down from 5.6 million in 1964.

Rising costs of Catholic education in the United States have boosted tvition from less than $100 a few years ago in subsidized schools to $300 or more, and in schools supported entirely by tuition to more than $2,000.

One factor in the financial difficulties, the statement said, is the sharp decline in the number of teaching clergy, nuns and brothers. These teachers, who are paid substantially less than laity, form about a third of the fulltime teachers in American Catholic Schools.

In encouraging teachers to take full advantage of professional organizations, it added fuel to the current controversy in the United States involving many bishops who oppose federal intervention through the National Labor Relations Board in disputes between Catholic school administrators and a growing number of of Catholic teacher unions.

The Vatican statement, stressed however, that "where difficulties and conflicts arise about the authentic Christian character of the Catholic school," the authority of the church's hierarchy "can and must intervene."