COROZAL, Panama (AP) _ Insurgencies against U.S. allies in Latin America have proved difficult to counter because they alternately simmer and rage and defy conventional tactics, U.S. military officers and civilian experts say.

They say insurgencies in this region pose a serious threat to U.S. national security interests, but are poorly understood and have had their importance obscured by bureaucratic battles within the military establishment.

Understanding such conflicts is important if direct U.S. military intervention is to be avoided, the strategists say.

''We're not used to acting with these long, ugly, socially unacceptable wars that don't fit in with our perceptions of conventional warfare,'' Col. Ed Smith said in an interview at his office at Corozal military installation. ''There are no front lines, no clear opposing forces.''

Smith heads a group operating under the U.S. Southern Command called SWORD, short for Small Wars Operational Requirements Division.

The unit's 20 military and civilian workers study guerrilla tactics to ''detect, deter and defeat small war threats.'' The Southern Command is the center for all U.S. military activity in Latin America.

SWORD researchers say the number of guerrilla insurgencies plaguing U.S. allies is most concentrated in Latin America, where there are about two dozen under way, including those in such countries as El Salvador, Peru and Chile.

It can be assumed that SWORD's stance will be echoed by supporters of the Reagan administration's push for $36.2 million in new aid for the Contra rebels fighting Nicaragua's leftist Sandinista government.

Smith and others point out that leftist guerrillas stage what are called ''prolonged popular wars.''

They say the American political system of presidential elections every four years sometimes makes it difficult to chart and stick to the long-range plans needed to help allies combat guerrillas.

''Wars like this go against our culture,'' said Col. John Waghelstein, a former U.S. Military Group commander in El Salvador and now a professor at the Army War College in Carlisle, Pa. ''We want short, violent wars with a clear middle, end, and a victory parade. Patience is not our strong suit.''

The war in El Salvador, now in its ninth year, is perhaps the classic example of a guerrilla war involving the United States.

The leftist guerrillas, grouped as the Farabundo Marti National Liberation Front, stage hit-and-run attacks. They hold no fixed territory or fortified bases to protect. They roam the isolated volcanic hills armed with M-16 automatic rifles.

U.S. officers say the war has reached a stalemate, despite almost $3 billion in U.S. economic and military aid to the government that has provided, among other things, helicopters, planes, artillery and troop training.

Max Manwaring, an ex-colonel and former deputy director of SWORD who now works as a civilian contractor, recently completed a written assessment of the Salvadoran situation.

It urges the United States to ''develop a coherent, rational, timely, and sytematic process designed specifically to strengthen an ally threatened by insurgency war.''

SWORD is one of several groups working for or with the Armed Forces to look into what has come most frequently to be called low intensity conflict.

Smith, two former officers working with him and several other active duty officers claim there is significant resistance within the Armed Forces to working jointly and strongly to deal with guerrilla wars.

U.S. military strength, technology and official doctrine traditionally focus on Soviet battlefield tactics, Smith said. Except for the special forces branches of the Armed Forces, most soldiers receive only conventional warfare training.

''That was one of our problems in Vietnam, we went in with solidly conventional soldiers,'' said Court Prisk, manager for BDM Management Services, a private contractor working with SWORD.

The Armed Forces can't even agree on a name for the non-conventional wars. The term counterinsurgency stirs up images of Vietnam, officers say. The phrase ''low intensity conflict'' insulted allies fighting guerrilla wars.

''Low intensity - ha. That's what the United States puts into it,'' El Salvador's head of military operations, Col. Mauricio Vargas, said in a recent interview in San Salvador.

American officers and soldiers agree: It's not low intensity conflict when the rifle bullets are whizzing by and the mortars are crashing.

So there is a new designation: high probability conflict.

''It's high probability because if we don't watch our p's and q's we'll have U.S. intervention, and we don't want that,'' Smith said.

''It is total war,'' the colonel said. ''But there is no one at the Department of Defense controlling, focusing, coordinating the efforts for it.''