The hierarchy of the Catholic Church in Spain, long associated with rightist forces here, has urged voters to abide by the electoral process although the Socialist party is expected to win power in October elections.

The document issued last night by the Spanish Bishops' Conference reflected a growing consensus in Spain about the inevitability that the Socialists would unseat the divided governing center party. The bishops urged Catholics to "accept the result of the polls, respect the incoming government and continue to collaborate with democratic institutions even though this be from a position of constructive opposition."

The Catholic Church has been tied closely to rightists following the Spanish Civil War in the 1930s, which was viewed by Gen. Francisco Franco as a Christian crusade against communism and atheism. But the church has been trying recently to distance itself from Francoism.

The Madrid daily El Pais said that the hierarchy deserved "the praise of lay sectors who might have feared inappropriate interventionism by the church in the electoral process."

A new opinion poll commissioned by the news magazine Cambio 16 and released today added to earlier indications of a Socialist victory. According to the poll results from a sample of 1,562 people, 33 percent of the voters had decided to vote for the Spanish Socialist Workers Party against 7 percent for its chief rival, the conservative Popular Alliance Party. If counting those merely leaning toward them, the Socialists would field about 51 percent of the vote, according to the poll.

The Socialists' proposed program is markedly moderate. The chief priority is unemployment, currently listed officially at 1.8 million or 14 percent of the workforce, and the party's main electoral pledge is to create 800,000 jobs.

Potentially, the most controversial feature of the Socialist program is the pledge to freeze negotiations over Spain's integration into the North Atlantic Treaty Organization's military command structure and the long-standing promise to stage a referendum on the issue of Spain's complete withdrawal from NATO.

The Socialists have refused to specify, however, when such a referendum would be held. Western diplomats believe that the Socialists may yet backpedal on the NATO issue.