Campaigning in the friendly confines of this city's Little Havana community, Ronald Reagan today accused the Carter administration of harassing anti-Castro Cuban refugees.

"There has been an attempt to harass those who are sympathetic with freeing Cuba," Reagan said at a bilingual news conference at the Centro Vasco restaurant, where he was cheered and applauded by partisan Cuban-American journalists.

Reagan offered no evidence to back up his charge, which caught even his own advisers by surprise. At the news conference, and again when reporters approached him immediately afterward, Reagan said he had "no examples" of this alleged harassment.

When a reporter persisted in seeking examples Reagan replied, "I've got to keep moving," and disappeared into a holding room.

Reagan advisers Edwin Meese III and Richard Allen also were unable to give an immediate example of what Reagan was talking about. But they conferred briefly with the candidate on a crowded street outside the restaurant, and Allen, a former Nixon administration foreign policy adviser, returned to reporters with three examples.

He said the Carter administration had eliminated a clandestine radio station that was broadcasting messages of freedom to Cuba, there was "excessive surveillance" of anti Castro refugees, and Cubans frequently were hauled up before grand juries upon any report of terrorist or illegal activity.

Reagan repeated these examples at a later news conference in Fort Lauderdale. He said would enforce the law against illegal activities but would not go beyond it into "harassment" of Cubans.

The White House had non comment on Reagan's statement.

Because of his staunch anti-Castro stand, Reagan is a favorite in the Cuban community here, which he carried by a wide margin even while losing the 1976 Florida primary to Gerald Ford.

But George Bush, aided by his position as former director of the Central Intelligence Agency and the bilingual campaigning of his 27-year-old son Jeb, also has been working hard for Cuban votes in Tuesday's Florida primary.

Today, within a few hours of each other, both Reagan and Bush campaigned at the annual Calle de Ocho (88th St.) festival here in the heart of the Cuban community.

Reagan, a Protestant, started the day by attending a Spanish-language Mass at St. Peter and Paul's Catholic Church. Then he laid a wreath on a stone memorial to those killed 19 years ago in the unsuccessful Bay of Pigs invasion aimed at toppling Castro from power.

Raymond Molina, a survivor of the invasion who spent two years in a Castro prison camp, shook Reagan's hand and predicted that he would be elected president. Molina said he expected Reagan as president would apply economic pressure on Cuba that eventually would topple the Castro regime.

At the news conference following this ceremony, Reagan promised that an administration led by him never would recognize Cuba as long as it denied basic human rights to its citizens.

Two hours later Bush showed up at the same festival, wearing a white Cuban shirt and bearing his own anti-Castro message.

"I will be a strong president," Bush said in his speech after a 10-block walk through the Cuban community. "I will not be taken in by Fidel Castro."

A poll appearing today in the Miami Herald showed Bush trailing Reagan in Florida. The poll showed Reagan with 42 percent, Bush 26, John B. Anderson, 4, John B. Connally 2 and undecided and others, 26. Carter led Sen. Edward M. Kennedy, (D-Mass.) 66 to 13, among Democratic voters, with 4 percent for California Gov. Edmund G. (Jerry) Brown Jr., and 17 percent undecided.