The momentous trial of nine former junta members in neighboring Argentina on charges of having presided over a campaign of murder, kidnaping and torture has become both a blessing and a curse for the cause of reestablishing democracy in Chile.

Opposition politicians and human rights activists here applauded the trial, in which five of the ex-junta members were convicted last week, as an important precedent in holding military leaderships accountable for offenses committed while in office.

But these same groups have worried that the Argentine example has made Chile's armed forces more hesitant to surrender power to a civilian government, out of fear that the same fate could befall them. This fear, say opposition members, has aided the effort of Chile's leader, Gen. Augusto Pinochet, to rally the armed forces around him.

"What happened in Argentina has been both good and bad for us," said German Molina, national secretary of Chile's autonomous Human Rights Commission. "It has shown us that justice is possible against the military, but Pinochet is now using the Argentine situation to warn other officers and strengthen his control over the armed forces."

Indeed, military commanders here are reported to have kept close watch on the Argentine proceedings, according to Chileans with contacts in the armed forces. "In the upper circles, the trial has been an obsession," said Federico Willoughby, the junta's first spokesman and now a private businessman. "They wanted news clippings, copies of speeches and court documents, everything to do with it."

One trial document widely circulated among military commanders and Cabinet members here was the defiant final defense speech of ex-admiral Emilio Massera, who justified the widespread terror tactics of the late 1970s and early '80s by saying that Argentina's war against left-wing guerrillas required unconventional methods. Pinochet recently lifted a phrase directly from Massera's parting shot by speaking of having won the physical war against left-wing forces but having lost the psychological one.

Wary of giving Pinochet another excuse to postpone a return to civilian rule, opposition politicians who signed a national accord in August calling for a transition to democracy included in that statement a commitment to avoid future human rights trials against the military aimed at "humiliation, vengeance or collective passing of sentence ad hoc."

While opposition members would like to see at least some military officers put on trial once democracy returns -- in order, they say, to preserve the military's prestige as an institution -- even moderate leftists appear willing to compromise on this point in the interest of gaining their first objective: the end of military rule.

"We are saying we can't build a future democracy on impunity," said Sergio Bitar, leader of the Christian Left party. "At the same time, we have tried to reassure the military that whatever justice there will be won't be massive and won't be vengeful. We are saying that what is likely to happen here will be more like what has happened in Brazil and Uruguay where no former junta members have had to stand trial than in Argentina."

In contrast to Argentina, where "dirty war" atrocities did not get prosecuted until after the military regime had been displaced in 1983 by the elected civilian government of Raul Alfonsin, Chilean courts already have begun reviewing allegations against military and police officers.

One much-publicized incident this year -- the killing in March of three Chilean Communists -- triggered a government crisis. The three men -- Manuel Guerrero, regional secretary of the teachers' union; Jose Manuel Parada, a human rights worker for the Roman Catholic Church, and Santiago Nattino, an illustrator -- were seized in broad daylight and found two days later on a road near the Santiago airport, their throats slashed.

An investigation by a government-appointed special prosecutor -- a low-key judge named Jose Canovas -- revealed police involvement and led to the suspension in August of 14 police officers as well as the dismantling of Dicomcar, the intelligence wing of the Carabineros, or national police force. The disclosures also prompted the resignation from the junta, and from his job as chief of the Carabineros, of Gen. Cesar Mendoza.

Last week, nine of the 14 policemen were given back their jobs, but charges are pending against the remaining five.

Spurred by the example set by Judge Canovas, several other justices have appeared more receptive to human rights complaints. Among "We have tried to reassure the military that whatever justice there will be won't be massive and won't be vengeful." -- Sergio Bitar, Christian Left leader the most important cases under investigation are the disappearance in 1976 of 10 members of the Communist Party and the two kidnapings this year of Carmen Hales, the daughter of a prominent opposition politician.

Providing an added impetus to these and other investigations -- and further embarrassing the government -- have been public confessions by several members of the security services, who have implicated military officers in specific instances of execution and torture.

But lawyers representing the families of some victims said that court progress is still frustratingly slow. Government agencies are said to be largely uncooperative in exposing the truth.

"The situation in the courts is essentially the same as before," said Roberto Garreton, chief attorney for the Vicariate of Solidarity, the human rights office set up by Chile's Roman Catholic Church. "The regime can continue to detain, torture, assassinate and exile people with a sense of impunity."

Chile's government spokesman and the interior minister denied several requests from The Washington Post for interviews.

The number of documented cases of people disappearing without a trace in the five years after 1973, when Chilean armed forces overthrew President Salvador Allende, is 668, according to the Inter-American Commission on Human Rights, an agency of the Organization of American States. A similar figure is given by the Vicariate of Solidarity, whose lawyers recorded the complaints of relatives of the missing.

In a report published in September, the OAS commission said that while disappearances ceased in 1978, a few new cases have been reported since the start of 1984.

The commission cited 851 torture cases from 1982 through 1984. Killings numbered 55 in 1983 and 1984 as a result of "undue use of weapons" by government forces to put down public demonstrations, the report said. The Chilean Human Rights Commission has reported 61 murders and 147 instances of torture so far this year.