The Reagan administration, citing the new Haitian government's moves toward democracy and improvements in human rights, yesterday released $25.5 million in aid that had been withheld because of rights abuses during the final weeks of Jean-Claude Duvalier's rule.

The State Department announced that Secretary of State George P. Shultz had determined that the improved rights situation in Haiti since Duvalier's departure permitted freeing the funds.

The aid was suspended in late January because the department decided that rights abuses in Haiti then were too flagrant to permit the certification required by Congress for dispensing direct U.S. assistance.

The aid halt was instituted when riots were sweeping the Caribbean island republic, the poorest country in the Western Hemisphere. The suspension was regarded as an important factor in forcing Duvalier's dramatic Feb. 7 flight to France and his replacement by a military-civilian Council of Government headed by Gen. Henri Namphy.

Shultz's action permits the release this fiscal year of $22.2 million in development assistance, $2.9 million in economic support funds to help Haiti's balance-of-payments problems, and $450,000 for military training.

These funds were part of a $53 million aid package approved by Congress for fiscal 1986. However, the other money flows to poor Haitians through private voluntary organizations and is not subject to the rights certification requirement imposed by Congress last year.

Explaining his findings, Shultz said that the new Haitian government "has released all political prisoners, restored radio broadcast freedom and disbanded the oppressive militia" known as Ton-Tons Macoutes.

He also said that while debate continues within Haiti over the timing for elections, the government appears committed to moving the country toward democracy.