Gen. Gustavo Leigh, the former air force chief of staff whose statements in favor of a return to parliamentary democracy here led to his ouster from Chile's ruling military junta five weeks ago, made his first public appearance as a civilian yesterday.

Leigh's mid-day walk through the crowded center of Santiago was carefully timed to attract both public attention and media coverage. It was generally viewed as a symbolic first step by Leigh to keep his name before the public as a possible alternative to President Augusto Pinochet. Pinochet appears stronger than ever at the moment, but he faces potentially crippling crises.

Some observers here think that Leigh and the 19 other air force generals who resigned with him could form the nucleus of an political opposition to Pinochet at a time when he must contend with the U.S. request for extradition of three officers charged with plotting the murder of former diplomat Orlando Letelier. Furthermore, Pinochet is involved in an increasingly bitter territorial dispute with neighboring Argentina.

Leigh's ouster from the junta came on July 24 after eight months of increasingly candid public statements. He disagreed sharply with Pinochet's plan to create some form of "institutionalized democracy" to replace the current military dictatorship.

Leigh said Pinochet's plan would take too long and would not give Chileans real democracy. Meanwhile, Leigh said, Pinochet was trying to personalize his own role as president and create a strongman form of rule like that of the late Francisco Franco in Spain.

Since his ouster, Leigh has become something of a hero to opponents of Pinochet although the former air force commander has professed not to be interested in a future leadership role. Nonetheless, the local press was notified Wednesday that Leigh would be walking from the office of a friend to his notary public's office, where he unsealed a net worth statement signed shortly after the 1973 coup that brought the military to power.

Leigh was met at the notary's office by a crowd of well-wishers and journalists. He was applauded as he entered the office and trailed by reporters afterward when he stopped for a drink and lunch at a downtown hotel.

Leigh said pointedly that he will return to the notary's office next week with a statement of his current net worth - a document which presumably will demonstrate the Leigh did not enrich himself during his years as a junta member.It is said here that other members of the junta might suffer some embarrassment if they reported their current assets as compared to those they had when they overthrew the late salvador Allende five years ago.

Although Leigh carefully avoided making any controversial statements, he did say that he largely agreed with statements made last week by Gen. Nilcanor Diaz, one of 19 air force generals who resigned immediately after Leigh was ousted.

Diaz said the junta's decision - thought to have been instigated by Pinochet - to get rid of Leigh was "exactly the same" as the way dissidents are dealt with in the Soviet Union. Leigh was not been jailed or his movements restricted but the press here was required to report only official statements about Leigh's removal.

Diaz also said he believed Chile has a strong democratic tratition and that any attempt to stop a return to real democracy - a clear reference to Pinochet's plan - "is against Chile's nature and will be condemned to failure in a very short time."

Diaz also criticized Chile's attempts under the current government to create a free-enterprise, capitalist economy. Diaz, who was minister of labor several years ago, said many Chileans have only bread and tea to each day and predicted that there could be "a violent reaction" if the conditions of the poor are not improved.

On his future plans, Leigh said only that he is not looking for work at the moment and has no plans to leave Chile. Asked by journalist what special qualities he might bring to a job, he said his specialty was "commander in chief."