IAMI, March 24 — Although dozens of his colleagues are imprisoned and his house is under police surveillance, Oswaldo Payá vowed today that his civic movement to bring reforms to Cuba would not be crushed.

Mr. Payá, the organizer of the Varela Project, a petition drive signed by more than 11,000 people seeking a referendum on personal, political and economic rights, is among a handful of dissidents who remain free after a crackdown last week by the Cuban authorities.

He said about 80 people — independent librarians, journalists and many of his group's regional leaders — were in jail on charges that could bring lengthy prison sentences after an islandwide sweep that began last Tuesday.

"They are trying to close the door on peaceful change," he said in a telephone interview from Havana.

The arrests came after several years of relative freedom in which dissidents assumed a higher profile as they met with a succession of foreign dignitaries, including former President Jimmy Carter, who publicly endorsed the Varela Project in Havana last May. Mr. Payá went on an international tour that included meetings with Pope John Paul II and the American secretary of state, Colin L. Powell.

Mr. Payá, who has won numerous international human rights awards, insisted that the recent arrests would not deter him.

"In no way will the project be stopped," he said. "There had been a flowering in Cuba of a peaceful movement for rights and reconciliation, to defeat this culture of fear. Cuba's spring is the Varela Project, which has been sustained by thousands and which will grow."

Governments and international rights groups have condemned the arrests and demanded that the Cuban authorities immediately release the prisoners.

The Cuban government has described the dissidents as subversives conspiring with James Cason, the chief American diplomat in Havana. Mr. Cason has met often with the island's dissidents and has spoken out publicly against the government of President Fidel Castro.

Asked if the arrests were meant to derail the Varela Project, a spokesman for the Cuban diplomatic delegation in Washington said he did not know.

"You have to get to the essence of the problem," said the spokesman, Juan Hernández Acen. "These groups are a minority in Cuba and represent nobody. They were not arrested for what they thought, but for acting against and threatening national security."

Mr. Payá said that he and his colleagues had been prudent in their dealings with Mr. Cason and that they did not accept money from the American government. He speculated that perhaps the Cuban authorities were trying to gain some leverage with the American government, which has imprisoned five Cubans on espionage charges.

Cuban officials have compared their roundup of dissidents to the United States' mass arrests after the attacks on the World Trade Center and the Pentagon. Mr. Payá said such accusations were part of the government's relentless defamation campaign against him.

"That mocks people's intelligence," he said. "We are claiming our rights."

But the threat felt by the Cuban government is real, diplomats and political analysts said, because the project relies on Cuba's own system to bring about change.

Mr. Payá and his supporters took advantage of a provision in the Cuban Constitution that says citizens can call for a referendum if 10,000 signatures are collected.

Yet despite the boxes of petitions that were delivered last May, and Mr. Carter's nationally televised speech in which he challenged the government to publish the project's proposals, officials have been mostly silent.

"They do not dare mention the project," Mr. Payá said. "To mention it will have people asking: `What is it? We want to learn about it.' And all who know it know it is something positive."