The first appointment of a Hispanic American to a post in the Carter administration was scheduled for today after a storm of protest from Hispanic Americans at the rejection of their candidate for assistant secretary of state for inter-American affairs.

Joe Aragon will be named a "domestic ombudsman, a transition team source said last night. Aragon was director of the national voter registration effort for the Democratic National Committee.

His brother, Manual, is deputy mayor of Los Angeles.

During his campaign, Jimmy Carter promised that Hispanic Americans would be consulted on appointments to the White House staff, the State Department and the Justice Department.

However, Hispanic American leaders became increasingly frustrated as the weeks of the transition passed with none of their candidates receiving jobs.

When it was learned yesterday that United Auto Workers official Esteban Torres was not going to be named assistant secretary of state for inter-American affairs despite a strong lobbying campaign on his behalf, the tide of protest swelled.

Manuel Fierro, president of the National Congress of Hispanic American Citizens, was polling members of the committee formed to advise Carter on Hispanic issues last night to organize a protest. Some committee members reportedly wanted to resign.

Herman Gallegos, a San Francisco police commissioner who has been working at the Carter transition office finding and passing on names of Hispanic American candidates for office said yesterday before the Aragon appointment became known "we're very disappointed."

He added, however, "the ballgame is not over and I believe good things will begin to happen."

Gallegos said the national Hispanic organizations had been cooperative with the Carter team and were now very frustrated.

It appeared last night that announcement of the Aragon appointment had been advanced to today in response to the protests from Hispanic groups.