Unions committed to back Walter F. Mondale for the Democratic presidential nomination see problems and conflicts ahead in primaries now that civil rights activist Jesse L. Jackson has entered the crowded race for the White House.
The concern of union political strategists is twofold:
* As a black candidate, Mr. Jackson almost certainly will draw substantial black labor support from Mr. Mondale, who, early in October, received the AFL-CIO's endorsement for the Democratic nomination. Most major unions have large black memberships and active civil rights records.
* Jackson has announced he will run not solely as a black, but as the candidate of a ''rainbow coalition'' of those seeking ''a just society and a peaceful world'' and who are opposed to President Reagan. AFL-CIO plans call for the creation of a similar coalition to support Mondale and to ''overcome the devastation of the Reagan administration's policies.''
The two coalition plans, one laid out by Jackson and the other by Lane Kirkland, president of the 13.7 million-member AFL-CIO, have the same general objectives. But conflict between the rival standard bearers is likely to be divisive in primaries, particularly in areas where blacks have been the most active in civil rights struggles. The Jackson candidacy could hurt Mondale in the South, the Midwest, and some parts of the Northeast.
Generally, union membership polls to select an AFL-CIO candidate were taken before there was serious talk of Jackson's candidacy. His name was not on most ballots. In one where it did appear, a poll among members of the International Association of Machinists, Jackson received a scant 3.4 percent of votes. The small Jackson vote might not be typical for labor generally; other unions have larger and more militant black memberships.
Both Jackson and the AFL-CIO plan national voter-registration drives, and these could also be a factor in primaries.
But the question remains: Who will get those added black and minority votes - Mondale or Jackson? At the AFL-CIO's recent convention, Benjamin L. Hooks, director of the National Association for the Advancement of Colored People, brought delegates to their feet with a reaffirmation of the historic bonds between labor and the civil rights movement.
Mondale forces say other black leaders remain committed to his candidacy. This could change, however; some black leaders who have been critical of organized labor's progress internally may now switch to the Jackson camp, joining the candidate in his criticism of the racial policies of labor unions.