The Reagan administration has offered to allow Gen. Manuel Antonio Noriega's handpicked chief of state, Manuel Solis Palma, to continue as Panama's acting president if Noriega agrees to give up power, according to U.S. and Panamanian sources familiar with the negotiations.

The proposed deal calls for Noriega to leave office as Panama's military commander and de facto ruler on Aug. 12 and for Solis Palma, a close Noriega ally, to remain as acting president through Panamanian presidential elections scheduled for May 1989, U.S. sources said.Under the pending proposal, Noriega would leave Panama and the administration would drop drug-trafficking charges against him. There were conflicting reports Saturday on when Noriega could return to Panama, but one U.S. source said it would be after the May 1989 elections.

The United States has refused to recognize Solis Palma, who replaced Eric Arturo Delvalle as Panama's president after Noriega fired Delvalle in February. The administration would continue to recognize Delvalle under the proposed agreement but would also accept Solis Palma, according to Panamanian opposition sources.

The prospect of Solis Palma remaining in control of Panama's governmental machinery during the balloting for a new president drew strong objections Saturday from Panamanian opposition leaders and on Capitol Hill. They said the offer would allow Noriega to maintain his hold over the government and control the outcome of the elections.

Juan B. Sosa, Panama's ambassador to the United States who has remained loyal to Delvalle, said Saturday that he told Assistant Secretary of State Elliott Abrams the plan was unacceptable when Abrams gave him a general outline of the proposal on Friday. Gabriel Lewis, a former Panamanian ambassador to the United States and an opposition leader, said he told Abrams in a meeting Saturday that if the administration agrees to allow Solis Palma to stay on and agrees to other reported parts of the deal, "it would be bargaining away the sovereignty of the Panamanian people."

U.S. sources described the negotiations as tense and fluid, with a number of different ideas under consideration. A State Department official said Saturday that no final deal with Noriega would be made before Monday, and Lewis and Sosa confirmed that they received the same assurances.

While emphasizing that no agreement has been reached, U.S. sources said the talks are at a delicate stage and said administration officials believe that either a deal will be struck within the next few days or the negotiations will collapse.

White House spokesman Marlin Fitzwater, as well as Abrams and other State Department officials, declined to comment Saturday on any aspects of the proposed deal.

U.S. officials are concerned that public disclosure of the plan might cause Noriega to call off any agreement. Noriega on Friday said that the negotiations had collapsed, but U.S. officials insist that the talks in Panama, under the direction of Michael G. Kozak, an Abrams deputy, are continuing.