The Republican Party gained its second formally announced presidential candidate yesterday when Los Angeles business consultant Benjamin Fernandex declared his determination to seek the GOP nomination in 1980.

"This is my first crack at public office," the 53-year-old self-made millionaire said, "but I think big . . . I fully expect to be the next president of the United States."

Fernandex said at a press conference yesterday, he expects to win because his status as "the first Hispanic Americans and other minority groups to back his candidacy with moeny and votes.

The confident, outgoing candidate asserted that political skeptics will be quickly convinced of his potential when he completes a $15 million fund-raising drive to finance his campaign.

"I can raise the 15 million bucks, and anybody who can do that is going to be a serious candidate," Fernandex said.

Fernandex learned fund raising in 1972 when he worked on the Finance Committee to Reelect the President, the financial arm of Richard M. Nixon's reelection campaign. Afterward, Fernandex was named chairman of a GOP committee to set up Republican organizations among Hispanics in a dozen large states.

He began talking seriously about a presidential bid last January. That talk dismayed some other Hispantic Republican leaders, who fear that Fernandez' candidacy will undermine the broader organizational effort. Fernandez seemed confident yesterday, though, that all Hispanic leaders in the party will eventually support him.

One other Republican, Rep. Philip Crane of Illinois has declared his candidacy for the presidential nomination in 1980. Nine more Republican hopefuls are preparing to enter the race.

Fernandez' political views seem to place him at about the middle of the Republican pack. He is conservative on most issues, but not as far to the right as Crane or former California governor Ronald Reagan.

He said the private sector can do a better job than the government in solving most domestic problems, including unemployment, agricultural production, and urban housing. But he said the government should try to spur private action in these areas.

The candidate called for a balanced federal budget, but could not identify the cuts he would make to eliminate the deficit. He promised to offer a detailed proposal within four months.

Fernandez castigated President Carter seeking to improve U.S. relations with Cuban President Fidel Catro, who, he said, is "the hemisphere's greatest violator of human rights," and for failing to warn the American people about communist movements in other Latin American countries.

At the heart of Fernandez' candidacy, however, is his obvious pride in his own achievements and his belief that his ascent from humble beginnings can be an inspiration to other minority group members.

"Traditionally our citizens have been able to climb out of our poor neighborhoods by making a decision to work hard," he said. "They need some inspiration, some motivation. My example, as president, might be one thing to do it."

Fernandez said he was born in a converted boxcar in Kansas City and worked his way through college and business school. In 1960, he started a Los Angeles consulting firm that helped investors organize banks. That business, he said, made him a millionaire.

After working under Maurice Stans at the Nixon re-election finance committee, Fernandez was questioned by the Senate Watergate committee and a federal grand jury pursuing charges that the committee promised governmental assistance in return for contributions from businessmen. Fernandez was never personally charged in any of the Watergate cases.