MANILA, SEPT. 17 -- President Corazon Aquino fired her two closest aides today in a major concession to her political critics and to the powerful military following last month's aborted coup.

The removal of Joker Arroyo as executive secretary and Teodoro Locsin as special counsel marks the apparent completion of a government overhaul aimed at reviving Aquino's embattled presidency.

Both Arroyo and Locsin are personally close to Aquino, but they had become major irritants to military officials as well as to business and political leaders. Diplomats and political analysts agreed that both had to go if Aquino hoped to reverse the apparent erosion of public confidence in her government.

The firing of the left-leaning members of the government was also among the demands of renegade Col. Gregorio (Gringo) Honasan, leader of the bloody Aug. 28 coup attempt, who is still at large. The view that leftists in government should be removed has gained wide support throughout the armed forces, according to recent surveys and soundings on military camps.

Arroyo's removal was widely praised by political and business leaders. "For most members of Congress, this is welcome news," said House Speaker Pro Tem Antonio Cuenco. "He has been perceived to be one of those factors causing disunity in the Cabinet."

Today's announcement comes one week after Aquino asked her entire Cabinet to resign to give her a free hand in reshaping her government. On Wednesday, Vice President Salvador Laurel announced he was quitting his Cabinet post as foreign secretary "irrevocably" because of policy differences with Aquino. Laurel's move prompted Aquino to unveil the first phase of her Cabinet shake-up, which included the replacement of Jaime Ongpin, her abrasive finance secretary, who has been criticized as favoring foreign lenders.

The departures of Laurel and Ongpin, and now Arroyo and Locsin, appeared to symbolize the final breakup of Aquino's original coalition of human rights lawyers, conservative businessmen and machine politicians.

The breakup began last November when Aquino fired Juan Ponce Enrile as defense minister. He is now the opposition leader in the Senate.

Aquino said Arroyo was leaving his position as executive secretary "in the hope that this would bring peace and quiet to the government." Many segments of the military believed Arroyo was a communist sympathizer because of his record of defending communists as a human rights lawyer during the martial-law rule of former president Ferdinand Marcos.

Arroyo was replaced by his deputy, Catalino Macareg Jr., a former corporate lawyer with a graduate degree from the University of Michigan who served briefly as Marcos' acting justice minister in 1979-80.

No replacement was named for Locsin, who held Cabinet-level rank as the president's special counsel and also wrote many of Aquino's speeches. Aquino said Locsin would remain a "consultant." Officials said he will probably continue writing speeches.

Aquino made no mention of whether she will make other high-level changes, but her press spokesman, Teodoro Benigno, said today's announcement would be the last. Yesterday, Aquino also removed two sub-Cabinet-level officials in charge of customs and immigration, two services that are widely perceived to be corrupt.

Gen. Fidel Ramos, the armed forces chief of staff, played down the role of military pressure in prompting Arroyo's ouster. "I would like to think that the president made these recent decisions, to remove some and appoint some, not because the military said so in a survey but because she needs to have a good team," he said in a nationally televised interview.

Still, it was far from certain that removing Arroyo would silence Aquino's critics.

One prominent opposition leader, former Marcos labor minister Blas Ople, said Arroyo's departure was insignificant because "The process of deterioration {of the government} is well under way. We see no way that President Aquino can reverse this decline."

Ople said opposition groups agreed this morning to set up a "shadow government" ready to take power if Aquino is forced from office before her term ends in 1992. He said Laurel was invited to join.

Several analysts agreed that with Arroyo's handpicked deputy replacing him, the structure of the executive secretary's office and staff would remain largely the same.

Aquino, in her statement today, made it clear that she agreed with Arroyo's policies and would continue to uphold them.

"I hope no one interprets his departure to mean that these ideals which fired our struggle for democracy have likewise departed as ideals for the new nation and government we established," Aquino said.

She praised Arroyo's "brave and tireless effort" in defending political prisoners and for helping restore the "broad freedoms" now enjoyed by Philippine journalists -- many of whom, ironically, have become Arroyo's most vocal critics.

Earlier today, Aquino received fresh support from the Reagan administration. Visiting Assistant Secretary of State Gaston Sigur met Aquino for about a half-hour in her office and delivered a personal message of "solid, total and complete support" from the White House.

"The admiration of the American people for you remains tremendous," Sigur said, according to Aquino's press spokesman Benigno.