President Reagan decried "special-interest politics" today even as he delivered a frankly political appeal for Hispanic American support.

"We have just emerged from the era of special interests, a sad time when coalitions were built with an eye toward the next election, not what's good for the country," Reagan said in a speech to the annual convention of the American G.I. Forum, a Hispanic veterans group.

His comments appeared to be directed at potential Democratic rivals, especially former vice president Walter F. Mondale, a front-running candidate for the 1984 Democratic presidential nomination. Reagan recited a list of complaints that were often made about former president Carter, and told the 2,000 delegates at the convention:

"Today, many who still practice the politics of the past would take you back to the days of lost opportunities, special- interest politics, tax and tax, spend and spend...Don't let America sink back into the boredom and mediocrity of collectivism, into the politics of envy, protest, and special interests."

Meanwhile, in his weekly radio speech today, Reagan said many Americans are "confused" about his policies in Central America. He urged the nation to "look calmly at the facts" of his military and economic efforts in the region, which he said would "give our neighbors the help they need without spooking ourselves in the process."

Reagan announced in his speech to the G.I. Forum that he has asked Vice President Bush to head an "interagency action group" on economic problems along the U.S.-Mexican border.

White House officials said they hoped to accelerate some existing federal programs to alleviate the difficulties caused by last year's devaluation of the Mexican peso. But White House Cabinet secretary Craig L. Fuller told reporters he could not specify any new federal aid that would be made available to the border region or put a dollar figure on the aid already being provided. "We'll start doing it not next year or next week, but today," Reagan said in announcing the effort.

Reagan's speech today came during a campaign-style swing designed primarily to bolster his support among Hispanics and veterans.

While Reagan has not yet announced that he will seek reelection, his speech today was laced with the themes and phrases of his past presidential campaigns.

Reagan received a noticeably cooler response from his predominantly Mexican- American audience than he did Friday from an audience of Cuban Americans, who have been a major source of support for him in the past.

The president's speech was replete with references to the patriotic military service of Hispanics. Reagan paid a special tribute to Dr. Hector Perez Garcia, a Mexican American who founded the G.I. Forum after World War II to help other Hispanic veterans fight discrimination.

"Now, I don't need to tell you, the struggle against discrimination is never over," Reagan said. "And this administration will stand by you as you continue the struggle."

"Are we practicing special-interest politics?" presidential spokesman Larry Speakes asked rhetorically during a briefing today. "No," he answered, breaking into a broad smile.

At the outset of his luncheon speech, Reagan ad-libbed a line about how much he enjoys being away from Washington.

Calling himself a "true Westerner," Reagan recalled how he had served enchiladas to Queen Elizabeth when the British monarch visited his ranch this year. The audience was silent.

Reagan used the phrase "special interests" in a critical manner a half dozen times during his speech, contending that Hispanics had been kept "at the bottom of the socioeconomic ladder" by "special- interest politicans" whom he did not name.

His speech was designed to convince Hispanics that they will make greater economic gains if they are not treated as a special group but are instead enabled to participate fully in society.

In an obvious reference to Carter, Reagan said Americans had been told from Washington that they "suffered from a malaise, that it was your fault, that you wanted too much, that you had to give up your hopes and tell your children not to dream as you once dreamed."

He also used another line that was a feature of his 1980 campaign speeches, saying:

"Remember when American embassies were sacked, when our hostages were taken, when our government seemed to be intimidated by every two-bit dictator in his hemisphere and elsewhere? Remember how our national defenses were crumbling?

"Today our defenses are being rebuilt. The Soviet Union's attempts to dominate the world are being checked...."

Reagan met Friday after his arrival here with representatives of the major Hispanic organizations. Raul Yzaguirre, president of the National Council of La Raza, said afterward that Reagan was well versed on bilingual education and immigration, but "on other issues he seemed to fumble and ramble and go on at length and so forth."