The leader of Iran's moderate political opposition called on Shan Mohammad Reza Pahlavi to abdicated and leave the country as martial law troops clashed with bands of protesters today in scattered incidents across Tehran.

Karim Sanjabi 73, the head of the National Front opposition grouping, told a rally of about 5,000 supporters that the shah should leave for the good of the country. It was the first time a senior National Front figure publicly called for his departure, although the Front previously indicated endorsement of the demand by allying itself with the hard-line Moslem religious opposition under the exiled Shiite leader Ayatollah Ruhollah Khomeini.

"I recently told the shah that the only way to restore law and order in Iran is for him to leave the country." Sanjabi told the rally on the ground of the Pahlavi Hospital in Tehran. He said he was repeating that demand publicly today.

Sanjabi was referring to a meeting with the shah 12 days ago when the chief of secret police came to Sanjabi's house unexpectedly and took him to the monarch's Naivaran palace.

Opposition forces said, meanwhile, that former National Front member Gholam Hossein Sadighi is pursuing efforts to form a civilian government to appease the opposition and pave the way for national elections next year.

According to one political opposition spokesman the shah is preparing to make a formal public announcement that he is willing to turn over power to a civilian administration and become a figurehead monarch.

Close associates of the shah have said he is ready to do this but that he still wants to retain control of the armed forces as commander in chief.

The opposition spokesman however, insisted the shah has accepted conditions posed by Sadighi which would effectively remove his control. One is that the "Ministry of War" would become the "Ministry of National Defense and be headed by a civilian answerable to the new government. Other conditions include the lifting of martial law and free elections.

The demonstrations, mostly by students of high school age, continued for the third straight day since schools briefly reopened after having been closed for a month and a half. The government ordered the schools closed again after Saturday's reopening turned into an occasion for renewed student protest.

Opposition sources said they had no reports of any deaths but that "many people." perhaps more than 20 were wounded in various shotting incidents

A mob tried to demonstrated outside the American Embassy for the second day this time approaching its through side streets from the rear. But Irania troops intervened to disperese them. Witnesses said at least one youth was wounded when a soldier shot him in the leg after he refused to leave and persisted in chanting slogans against the shah.

Two truckloads of troops guarded the front of the embassy and there were no report of further incidents.

In late morning about 150 persons including some women in full-length black veils marched down Aryamehr Street carrying pictures of Khomeini and chanting "Death to the Shan." They stopped at an intersection outside the Intercontinental Hotel where most foreign correspondents in Rehran are staying.

The crowd was starting to march past when two military armored cars rolled up in intersecting streets and about 20 soldiers in combat gear jumped out. The demonstrators started runing up a side street at the sight of the soldiers who fired a tear gas canister as the mob escaped.

A few remaining youths exhorted motorists to sound their horns in protest. A cacophony of beeping and honking ensued as the confused souldiers tried to sort out another one of Tehran's massive traffic jams.

Troops often have seemed to have great difficulty reaching such trouble spots because ot the nightmarish traffic in this smog-bound city. The situation works to the advantage of the small groups of protesters who often leave quickly when the soldiers finally arrive only to regroup somewhere else later to stage another demonstration.

Several such protests occured at different times along Villa Avenue where mobs set up fiery barricades to further complicate troop movement. At one main intersection, about 50 youths set bonfires across a major street only a block from a square where a truckload of soldiers was deployed. The troops intervened when the mob ordered passengers out of a doubledecker city bus, positioned it across the avenue and prepared to set fire to it.

The soldiers came running and fired their automatic weapons into the air and both mob and bystanders ran off in all directions.

United Press International reported that a strike by oil workers appeared to gain momentum pushing down today's production to about 1.5 million barrels compared to the nation's normal output of nearly 6 million barrels a day at this time of year.

A Soviet Hyrushin airliner evacuated about 50 Soviet oil experts and dependents from the strike-bound oil town of Abandan. UPI added. The Soviets were working at the Kharg Island oil export terminal also hit by the strike.

Paul E. Grimm an American oil executive was killed by terrorists Saturday. Grimm and other forigners in the oil fields had received death threats. CAPTION: Picture, Karim Sanjabi, head of political opposition to shah, addresses Tehran rally, AP