Gen. Mario Benjamin Menendez and four other generals who commanded Argentine troops on the Falkland Islands have been removed from their posts in what the Army commander in chief described as the prelude to a major military shake-up.

The commander, Gen. Cristino Nicolaides, who has struggled to control widespread unrest in the Army this month, announced the action last night. He said the high command had decided to "rapidly restructure the Army" in order to stabilize its ranks and "professionalize" its operations.

The Army command also announced the replacement of two colonels, eight lieutenant colonels and 10 majors. Most were stationed on the Falklands as field commanders after Argentina's April 2 invasion, officials said.

The extensive reassignment of commanders comes at a time when Argentina's armed forces remain sharply divided over the invasion and the course of military rule. The continued feuding is regarded as a growing threat to the Army government of Gen. Reynaldo Bignone, which has been unable to gain public confidence for its emergency economic program or its planned 18-month transition to civilian government.

In the Army, according to well-informed sources, field commanders generally have been matched against their staff colleagues and superiors in Buenos Aires in the determination of how Argentina failed. Some brigade generals and many junior officers also are reported to be deeply unhappy with the top rank of military commanders, including Nicolaides.

Menendez, the three other brigade generals and two colonels temporarily were assigned to Nicolaides for "review of orders"--a measure that Nicolaides said did not indicate a judgment of blame against them for Argentina's defeat by Britain in the 11-week conflict. "This has been done to achieve the most absolute justice," he told Argentine reporters at a briefing.

The action was interpreted by military observers here today as an effort by Nicolaides to cool tensions in the Army and consolidate his own command while a special commission continues an investigation of the conduct of Menendez and other officers in the failed campaign, which cost Argentina close to 2,000 casualties.

Military analysts said that the replacements leave the officers in a state of limbo. Although not yet officially sanctioned or disgraced, they will be obliged by military tradition to retire from the service if they are not awarded new commands in the coming months.

Nicolaides said the Army officers suspended from their commands could be sanctioned or honored, depending on the conclusions of the five-member investigative commission established earlier this month.

In a debate that has as much to do with politics as with determining who was responsible for the military failure, some Army officers contend that Argentina's troops were poorly managed in the field and that the terms of Menendez's surrender June 14 were unjustified, sources said. But other officers assert that the real blame for the loss falls on the ruling junta members and other high policy-makers who launched a conflict that could not be won.

One source close to the officers' corps said that many staff officers openly opposed the management of the conflict with Britain by the former president and Army commander, Gen. Leopoldo Galtieri, by May, more than a month before the defeat. Now, those officers are complaining that their superiors, the 10 division generals who held the top rank of command below Galtieri, did nothing to check his determination to fight for the islands rather than compromise on Argentina's demands for sovereignty.

Military analysts say the outcome of these disputes--now channeled partly through the investigative commission--could largely determine the professional future of the Argentine Army and the military government. Although only field commanders and lower-ranking officers have been singled out for judgment through temporary suspension from commands, the top division generals who make up the base of power for Bignone's government could be reassigned or forced to retire, sources said.