Suddenly released after 29 years of repression, demands for political change are sweeping over Haiti like a Caribbean hurricane too powerful and unpredictable to control.

Thousands of youths, emboldened by success in driving Jean-Claude Duvalier from power, are reveling in a discovery that for the first time they can challenge authority and not only get away with it, but also force a response.

So far, they have proved to be the country's main political force in a chaotic array of competing power centers.

More than six weeks after Duvalier's fall, their power in the streets has yet to be harnessed by civilian political leaders able to channel the demands for change and deal with the military officers who inherited authority when Duvalier fled.

The result has been an explosion of political activity with little, if any, direction, atomized in unrelated groups, causes, or aspiring presidential candidates. The one cause most street youths appear to have agreed on recently is a growing call for the military to step aside for a provisional civilian government even before elections can be organized.

"Bum palais-la, bum palais-la," they chanted in Creole during a recent demonstration challenging the military's right to rule. "Turn over the palace, turn over the palace."

Lt. Gen. Henri Namphy, who heads the National Council of Government, fired two council members and a key adviser on March 21 who were associated in the public mind with Duvalier's abuses. Namphy's action came in response to weeks of demands by demonstrating youths. But by the time he moved, the popular demands had expanded to include his own removal.

Diplomatic and Haitian sources said some military officers, uncomfortable with the disorder, have discussed the possibility of moving against Namphy. These sources said the contacts, among a small group of colonels and majors, appeared so far to be tentative and inconclusive. But they were enough to send rumors of a coup d'etat percolating through Port-au-Prince a few days ago.

The extent of U.S. influence over these officers has remained unclear. The Haitian military, abiding by tradition, has mostly kept silent. Neither U.S. Ambassador Clayton McManaway nor his military attache has been available to reporters to discuss U.S. contacts in the military.

Publicly, however, the Reagan administration has offered strong support for Namphy. Within one month of Duvalier's departure, Washington flew in $384,000 worth of riot gear including 150 shotguns with 10,000 rounds of birdshot, 5,000 tear gas canisters and some radios and bulletproof vests.

In addition, a ship bearing $2.3 million in emergency U.S. wheat donations arrived two weeks ago.

Haitian youths have complained angrily that the United States also sent in the hard rubber truncheons used March 21 to beat a number of protesters in Port-au-Prince. The U.S. Embassy issued a statement calling this an "unfounded allegation." But young men burning tires during disorders March 24 said they did not believe the denial.

Aspiring political leaders have said in interviews that such youth often has unrealistic demands and attitudes because of inexperience and lack of education. The political figures appeared unanimous, for example, that the military must remain in power for a time until elections are held because no civilian could manage the country under present conditions. This assessment was in direct contradiction to demands shouted by the demonstrating youths..

"A civilian government without the military, what is that worth?" said Gerard Gourgue, who resigned March 20 as the council's longtime anti-Duvalier leader.

Gourgue and other civilian figures have been in contact in an effort to work out a civilian leadership coalition as a moderate counterweight to the military, said Lafontant Joseph, one of those involved. But Hubert de Ronceray and Gregoire Eugene, both presidential candidates, said they would not be part of the group and urged instead that the military work faster to organize elections.

"Everyone is a presidential candidate," said DeRonceray. "What kind of association can we form?"

Rene Theodore, the Haitian Communist Party leader recently returned from exile, has suggested instead a "national debate" to select a replacement for Namphy's National Council of Government. In a public document, he urged that each of Haiti's nine regions delegate a spokesman for the debate.

The Roman Catholic Church, which played a leading role in toppling Duvalier, has pulled away from the present confusion, apparently to leave the way clear for political leaders. Activist priests have remained close to the street demonstrations, however.

One, the Rev. Jean-Bertrand Aristides, led a small demonstration recently in which students sang for peace and changes in the government at the same time. "Until we get rid of the Duvalier system, we will continue to say no, no, no," Aristides told reporters.

Aristides said the will of the people has to be respected; if they say the military must leave the government, that is the solution.

Other demonstrators have been similarly rigid. A group of taxi drivers demanded improvements in a crowded street recently, for example, and added in a message to the government:

"We will wait only eight days for the Department of Public Works and Transport to make known its plan to carry out improvement projects . If not, we will consider the department is no longer competent and will take the appropriate measures."