MIAMI (AP) _ Nelson Mandela's scheduled arrival in Miami tonight has driven another wedge between blacks and Cuban-Americans in this racially divided city.

The South African anti-apartheid leader has been greeted as a hero in New York, Boston, and Washington, D.C. But South Florida politicians have refused to honor him, and area Cuban-Americans are calling for mass protests during his address Thursday at a labor convention in Miami Beach.

Black leaders, in turn, are calling for counterdemonstrations and have condemned the politicians for ignoring the message of hope Mandela could bring to U.S. blacks.

''To reject Mandela is to reject us and that is very deep. It's psychologically devastating,'' said Johnnie McMillian, head of the Miami-Dade chapter of the National Association for the Advancement of Colored People.

Mandela's visit was welcomed until last week, when he defended Cuban leader Fidel Castro, Palestine Liberation Organization leader Yasser Arafat, and Libyan leader Moammar Gadhafi for their help in the early years of the African National Congress' struggle against South Africa's racial separation laws.

The heavily Cuban city of Miami immediately withdrew a planned proclamation in Mandela's honor.

Miami Mayor Xavier Suarez and four other area Cuban-American mayors criticized Mandela for his insensitivity to human rights in Cuba, and Mayor Alex Daoud of largely Jewish Miami Beach also condemned Mandela for praising Arafat and Gadhafi.

Representatives from the Southern Christian Leadership Conference and other black groups responded Tuesday by marching to Miami's City Hall with an ultimatum: declare Thursday ''Nelson Mandela Day'' - or face a backlash from black voters in the next elections.

''It would be a profound international embarrassment to every member of this city if the city of Miami fails to acknowledge and honor Mr. Mandela, a man who is the living embodiment of courage and human dignity,'' said Ray Fauntroy, executive director of the SCLC in Miami.

But the commissioners, including the panel's lone black member, Miller Dawkins, who was elected with widespread Cuban support, wouldn't budge.

''Anything that smells of Fidel Castro, we have to be wary of. There is no compromise in the Cuban community when it comes to Castro,'' said Miami Commissioner Victor DeYurre.

A continuous stream of calls to local Spanish-language radio stations have been almost unanimous in condemning Mandela.

''We don't care for the black leaders. We care about Cuba. Our case is Cuba,'' said outspoken Cuban activist Alfredo Zayden, chairman of the Free Cuba Committee.

However, local Jewish leaders reiterated their opposition to apartheid and tempered their criticism for Mandela's comments on Arafat and Gadhafi with praise for his work against anti-Semitism.

''We share a common destiny as citizens of Dade County. There is room for us to agree and disagree on issues of principle,'' said Arthur Teitelbaum, director of the Anti-Defamation League of the B'nai B'rith in Miami.

Feuds between blacks and Hispanics in Miami have simmered for more than a decade. The latest friction grew from the January 1989 shooting of a black motorcyclist by a Colombian-born Miami policeman, sparking three days of rioting.

In Los Angeles, county supervisors also clashed over Mandela's support for Castro, Arafat and Gadhafi, but they still declared Friday to be Nelson Mandela Day.

Supervisor Mike Antonovich argued against honoring Mandela, who is scheduled to arrive in Los Angeles on Friday on the last leg of his U.S. speaking tour. He called for Mandela to renounce his support for Arafat, Gadhafi and Fidel Castro.

''Because Arafat and Gadhafi have been responsible for so much bloodshed in the Middle East and all three have contributed to terrorism, I think we should ask that Mandela repudiate his support for them,'' Antonovich said Tuesday.

But Supervisor Kenneth Hahn said Mandela had made it clear he supported Arafat, Castro and Gadhafi because of their opposition to the South African government's policy of apartheid, or racial segregation.