Splits within the government of President Corazon Aquino that had become apparent before this week's abortive coup now have developed into open friction between influential Cabinet members and segments of the powerful military.

The humiliation of forces loyal to former president Ferdinand Marcos early in the week gave a decided boost to Aquino's fortunes. But the episode also presented her with a serious test of her leadership when antagonisms between the civilian and military wings of her government boiled over at a heated midweek Cabinet meeting, according to accounts from participants on both sides.

The dispute, which centers on strategy toward the Philippine communist insurgency, is showing signs of affecting U.S. relations. Prominent Cabinet members here express irritation at what they describe as Washington's prompting of Manila to be tougher with the rebels.

Citing a steady stream of public and private statements by U.S. officials from Secretary of Defense Caspar W. Weinberger to Ambassador Stephen Bosworth, Executive Secretary Joker Arroyo, a long-time Aquino confidant, said in an interview: "Washington sometimes seems to be off the ground. They keep advising us just like in Marcos' times. We can't have another Vietnam, blindly following Washington's advice."

Assistant Secretary of Defense Richard L. Armitage was quoted prominently in the press here today as saying: "The military situation is serious and getting worse. . . . Mrs. Aquino is going to have to let her forces take the proper action against the insurgents."

In Washington, Philippine Ambassador Emmanuel Pelaez warned this week that the United States could face increasing difficulty over its bases here if it did not show greater support for Aquino's policies. She is to meet with President Reagan and address Congress in mid-September.

The Cabinet confrontation in part reflects serious policy differences and in part is a legacy of the odd amalgam of forces that came together to sweep away Marcos's rule in a tide of "people power" in February. Political observers say the rift can be healed if Aquino makes the right moves as she becomes more adept at wielding power.

As Arroyo noted, the takeover bid by the group loyal to Marcos "forced everything into the open. The lines are drawn."

The Cabinet conflict found in one camp Defense Minister Juan Ponce Enrile and Army Chief of Staff Gen. Fidel Ramos, who had held prominent positions under Marcos, and, in the other, Aquino and Arroyo and others who had suffered at the hands of Marcos' military.

With Aquino generally above the fray, the two camps had been feuding openly for the last two or three weeks, with Enrile and others in the military speaking out against Aquino's strategy of seeking to negotiate with communist insurgents and offer amnesties to win over their fighters, while at the same time threatening to take action against the Army on human rights abuses.

There also had been a move against some of Enrile's financial interests.

Military leaders familiar with last weekend's takeover bid say that many of the 300 soldiers who joined Marcos' ex-generals and colonels at the Manila Hotel did so because they were told Enrile and Ramos supported the move. But the two quickly pledged their loyalty to Aquino.

Then Enrile offered an amnesty to the military involved in the attempt, and got the major headlines in the Manila press for resolving the matter. This aggravated the tensions in the Cabinet. While Aquino later told the Cabinet she supported Enrile's move and that he had acted on her instructions, participants agree that there was at a minimum some misunderstanding between them.

Aquino's apparent intention was to offer clemency, but not a total amnesty, one top military official said, "but she used the politician's somewhat imprecise language while he used the lawyer's precise definitions." "Enrile argued that the best way was to coopt them. But if their idea is coopt this riffraff, a gang of torturers, no way," one Cabinet minister said of the pro-Marcos officers involved in the putsch, some of whom allegedly were involved in flagrant abuses during the past rule.

A senior military figure, arguing that the Army was struggling to rebuild and was capable of quietly putting its own house in order, said, "The choice is between unity and the certainty it won't happen again." Clearly favoring the Army unity option, he went on:

"It's hard to judge motivations, but there were some in the Cabinet who seemed to be pressing goals beyond a narrow difference over what the punishments should be."

Junior officers expressed their feelings more sharply, charging that the latest attacks against Enrile were just part of a general government assault on the military's integrity.

"We get punished and the NPA communist New People's Army gets a picture in the paper glorifying it after one of our patrols is ambushed," one young officer said bitterly.

Officers at this level, many of whom are active in the Reform Armed Forces Movement that played a major role in swinging military support away from Marcos, quickly cast the current debate in the context of a power struggle and a battle over policy toward the insurgency.

One officer, discussing the government's team dealing with the insurgency issue, said "these people are amateurs. You don't go into a judo club having read a few books and take on the old master. You will get clobbered."

For another, it is a question of confusion in the field, where the fighting and killing continue daily. "We can't just sit by and let them destroy the Army. Field officers are confused. If I am on patrol and I go after someone, I may end up facing human rights charges. If I don't, I may get shot."

Cabinet officials say such thinking is a distortion of what the government has done and a failure on the part of the military to recognize that the Philippines has a new leader with broader priorities than the Marcos regime that led the country to the brink of economic disaster.

"In 1972, there were only 500 in the NPA. Now there are 14,000 to 18,000. The Marcos strategy of all-out assault has been wrong," Arroyo argued. "The defense minister and the armed forces are continuing the Marcos strategy. Since it has been proven wrong, we have to change it. . . . We inherited an Army that is not ours. We have to make the most out of it."

Arroyo said the government is committed to revitalizing the military, with new officers and with increased pay and medical and other facilities to improve the morale of the troops. He criticized what he said was a U.S. emphasis on more sophisticated equipment while basic needs go unmet.

"If the cease-fire talks don't work . . . then we can unleash the armed forces . . . . We will leave the strategy to them, but first we must exhaust all possible remedies."

There are those at the upper level of the military who do not argue with the idea of a respite for rebuilding, even if they remain uneasy about some of the government's other policies.

"We have always tried one way -- the Marcos way -- and it hasn't succeeded. We should give it a try," an officer said. "If we had to give it a hard approach right now, considering the state of deterioration of the armed forces from the Marcos era, we could fall. We could be embarrassed. We can take advantage of a cease-fire, too, to reequip, to retrain."

Some are counseling Aquino to overcome a natural suspicion of the military and to to develop a closer personal relationship, as commander-in-chief, with her top generals. A dinner for newly appointed generals tonight at the presidential palace is seen as part of such a strategy.

Special correspondent Abby Tan contributed to this report.