Jocelyn Marcellus was bitter yesterday as he recounted the frustrations that he and many Haitian immigrants feel as they watch Cuban refugees welcomed to the United States with federal assistance while Haitians in South Florida and elsewhere daily fear deportation.

"The way they welcome the Cubans, they should welcome us," Marcellus said through an interpreter yesterday at a press conference outside the State Department.

"When the Cubans arrive, they get hotel rooms, money for food and we get nothing," said Marcellus, 21, who fled Haiti under the regime of president-for-life Jean-Claude Duvalier last February.

Marcellus is one of about 10,000 Haitians who await President Carter's decision whether to parole them as political refugees. The president has until May 15 to do so, when his authority to grant asylum on a group basis, as was done with Cubans and Vietnamese, terminates.

About 60 Haitians arrived yesterday to begin a weeklong vigil from 4 p.m. to 8 p.m. daily in Lafayette Park in support of political asylum. Yesterday's press conference, march and rally kicked off that effort. A national demonstration is scheduled for Sunday in front of the White House from 1 p.m. to 5 p.m.

About 25,000 Haitians have settled in the United States in the last decade, most of them refugees from poverty and repression.

Haitians say they have found only rejection, no work permits that would allow them chances to earn a living legally, and a hostile Immigration and Naturalization Service bent on deporting Haitians as "economic" rather than political refugees.

The Haitians maintain that if deported, chances are great that they will be severely punished, if not killed.

"These people are our invisible boat people," said Rick Swartz, a lawyer representing the Haitians in a court case in U.S. District Court in Miami. The case charges that INS ignored usual processes and decided to single out Haitian boat people for deportation.

"For seven years these people have suffered severe discrimination because of their race, because they are poor and many are illiterate," Swartz said. "But these people are fleeing a regime that is supported by the U.S. government for the past 22 years. They are asking for political asylum because they believe they will be persecuted if they return."

To a small crowd of mostly media, several of the Haitians described the conditions they left begind in Haiti. They said they hoped that the United States would no longer support Duvalier.

"We feel frustrations about this U.S. policy, and it is a big insult to us to treat us as second-class boat people," said Father Gerard Jean-Juste, the director of the Haitian refugee center in Miami.

According to Jean-Juste and others, Haitian refugees are nearly starving in the streets of Miami, denied chances to work or federal assistance. Florida state and local governments have contributed aid, as well as some religious organizations, but much more is needed, they say.