Panamanian leader Gen. Manuel Antonio Noriega and Lt. Col. Oliver L. North planned secretly in 1985 to train Nicaraguan rebels in Panama, according to Jose I. Blandon, a former top Noriega aide who is now under 24-hour guard by the U.S. Marshals Service as a witness in federal drug and corruption investigations of Noriega.

Blandon alleged that the training of between 200 and 250 contras took place from July 1985 to May 1986. Several knowledgeable military and other U.S. officials expressed skepticism this week that the plan was ever carried out, but a well-placed government official said yesterday there is intelligence information to support Blandon's report that Panama trained contra fighters.

Blandon alleged in interviews over the last week that in return for the secret contra training, North agreed that he would try to get the U.S. government to assist Panama with its debt crisis in late 1985. Private and international development bank loans of more than $200 million were made to Panama over the next year, according to records and other officials, though a number of banking and Treasury Department officials said that neither North nor the White House played any role in the arrangements. The loans helped avert economic collapse in Panama, which had a $3.8 billion debt in late 1985.

Congressional and other sources said that the Blandon contra training allegation is the latest evidence suggesting that North, the National Security Council aide fired for his role in the Iran-contra affair, turned to Noriega for critical assistance in 1984-86, when Congress had restricted U.S. aid to the contras.

Sources said that classified White House computer notes reviewed by the House and Senate Iran-contra committees describe discussions between North and Noriega on possible Panamanian assistance to the contras.

For example, in one previously unpublished September 1986 internal White House computer message, North reported that Noriega had pledged to help the contras if in turn North or the White House would help the Panamanian leader improve his image, sources said.

Blandon, 44, a former top civilian political adviser to Noriega, was fired by Noriega as Panama's consul general in New York last month. For several months last year, Blandon had been Noriega's secret emissary to the Reagan administration in an unsuccessful effort to work out an arrangement to allow Noriega to step down and permit a move toward civilian government and democracy in Panama.

Noriega is the target of a Miami federal grand jury investigation examining his ties to the multibillion-dollar Latin American narcotics trade. Federal prosecutors are expected to seek an indictment this week, sources said.

Through a spokesman, Noriega has denied Blandon's corruption allegations and said that Blandon was not a close adviser or associate.

In the course of hours of interviews with The Washington Post, Blandon said he was present at a 90-minute Noriega-North meeting on a yacht in Panama in which the contra training proposal was first discussed. Blandon said he believes the meeting occurred in June 1985. North requested arms, training and intelligence assistance for the contras, according to Blandon's recollection. Blandon said that he prepared for Noriega at the time a two-page memo summarizing North's requests at the meeting.

After Panama's secret contra training began in July 1985, Blandon said, he visited the training site known as the Jose Domingo Espinar Training Center. The center is at the former U.S. Fort Gulick, which housed the U.S. Army's School of the Americas until it was given to Panama in 1984 under provisions of the Panama Canal treaties.

A Panamanian officer, identified by Blandon as a Col. Elias Castillo, who was in charge of the base, pointed out 45 to 50 contras undergoing training at that time, according to Blandon.

Blandon said he was told that the contras were instructed in mortars, surface-to-air missiles and intelligence. He said he was told that the training was being carried out both by Panamanian officers and off-duty U.S. military personnel attached to the Southern Command base in Panama.

Blandon said that he did not see any U.S. military officers during his visit, but that an aide to Castillo told him about the U.S. personnel.

"The training was being done by the Panamanians and by certain officers of the United States that came late in the afternoon," Blandon said.

Asked about this allegation yesterday, the Pentagon said: "Neither we at DOD {Department of Defense} nor {the Southern Command} have any record or knowledge of such activity."

At a second North-Noriega meeting that Blandon said he attended in Panama in October 1985, Noriega said Panama was in serious financial condition. "The only thing we need help with is money," Blandon quoted Noriega as saying. According to Blandon, North said: "I will try to do the best I can."

During the 15 months following the Noriega-North meeting, Panama received an infusion of additional loans and economic assistance, some of it from the U.S. government. Economic assistance to Panama from the Agency for International Development, which had been running at a maximum of $13 million in previous years, jumped to $74.5 million in 1985, according to AID records provided by a spokesman.

According to well-placed banking officials, Panama's commercial creditors refinanced Panama's debt payments and provided other credits and loans totaling $148 million.

Blandon said that the basic financial situation had stabilized for Panama by March 1986. He said that both Noriega and he credited North with assisting Panama. "He solved all our problems with the U.S.," Blandon said.

North or his attorney could not be reached for comment.

The record of the congressional Iran-contra committees shows that North and Noriega worked together at times, and a military source said that North visited Panama a number of times each year during the period he managed private supply channels to the contras in 1984-86.

The Iran-contra report said that "North received an offer {in 1986} from a third party to engage in sabotage and other activities inside Nicaragua." Then-Vice Adm. John M. Poindexter, who was national security adviser, "approved the sabotage plan, but instructed North not to become involved in conspiracy or assassination." That plan was never carried out, the report said.

Staff writer George C. Wilson and staff researcher Melissa Mathis contributed to this report.