The Supreme Court, in what dissenters called an endorsement of "parochialism and hostility" toward the foreign-born, ruled yesterday that resident aliens can be denied even low-level government jobs solely because they are not U.S. citizens.

The 5-to-4 decision upheld a California law barring noncitizens from working as deputy probation officers or as "peace officers" of any kind. Justice Byron R. White, writing for the majority, said these sorts of jobs form part of the "basic governmental processes" which may exclude "those outside the community."

The decision comes at a time of increasing controversy about immigration, and a time of rising unemployment rates and widespread government layoffs. While it is not a radical departure from past rulings, it appears to sanction the handling of those problems with one standard for citizens and another for noncitizens.

It also continues the Burger Court's trend, especially pronounced in the past two years, to deny major expansions of constitutional rights when in confrontation with governmental authority.

The decision produced an unusually strong dissent, read in full from the bench by Justice Harry A. Blackmun. "Today's decision rewrites the court's precedents, ignores history, defies common sense and reinstates the deadening mantle of state parochialism in public employment," he said. Justices William J. Brennan Jr., Thurgood Marshall and John Paul Stevens joined Blackmun.

Jose Chavez-Salido and two other Spanish-speaking residents of Los Angeles County brought yesterday's case. All were graduates of colleges in this country and long-time residents. They were not, however, citizens. And although Chavez-Salido, for example, scored 95 out of 100 on an examination for the job of Spanish-speaking deputy probation officer, California's law denied him and the others the job.

The Supreme Court has in the past extended to noncitizens who are legally resident in the United States a large number of the same rights citizens enjoy. They cannot be denied the right to private-sector jobs or to welfare solely because they are not citizens, for example. But in prior rulings, the court has drawn the line at government jobs involving policy making and significant power.

The question yesterday was whether a position as deep into the bureaucracy as a deputy probation officer--responsible for supervising criminal offenders released on probation--is one of those jobs.

White said it was. A probation officer enjoys some of the same "coercive" authority as a police officer, he said, and fits within the "general law enforcement" category where significant authority is exercised. A probation officer "has the power both to arrest and to release those over whom he has jurisdiction" and "the power and the responsibility to supervise probationers and insure that all the conditions of probation are met . . . ."

A state must be extremely careful when denying aliens some privilege to further some economic interest, White said. But when it is advancing a political goal, as it was in this case, a state has broader discretion.

"The exclusion of aliens from basic governmental processes is not a deficiency in the democratic system but a necessary consequence of the community's process of political self-definition," White wrote.

"Self-government, whether direct or through representatives, begins by defining the scope of the community of the governed and thus of the governors as well: Aliens are by definition those outside the community."

The dissenters said the job of deputy probation officer is too low in the hierarchy to exclude aliens. More importantly, they said any act of discrimination against resident aliens must be carefully thought out and absolutely necessary to achieve some important government goal.

California's law was too sweeping, they said. Without offering any real justification, it denied noncitizens jobs not only as probation officers but as toll takers, cemetery sextons, fish and game wardens and voluntary fire wardens.

"California's exclusion of these appellees from the position of deputy probation officer stems solely from state parochialism and hostility toward foreigners who have come to this country lawfully," Blackmun wrote.