Iran's parliament was dissolved yesterday as a new military government took control and imposed severe measures to put down a growing insurrection against Shah Mohammad Reza Pahlavi.

The shah, who will continue to reign as monarch, but will apparently play a curtailed role in governing Iran, promised in a nationwide broadest to form a national unity government and hold free elections "after order is restored." If held, the elections could result in constitutional monarchy, limiting the shah's power after 15 years of dictatorship.

The shah said he has appointed a caretaker government and accepted the Cabinet's resignation "to avoid the collapse of the economy and to bring about peace."

The new government, under the leadership of Prime Minister Gen. Gholam Reza Azhari, chief of staff of the armed forces, sent tanks and heavily armed soldiers into Tehran to restore order. Agents of SAVAK, the secret police, began arresting opposition leaders and clamped censorship on newspapers and broadcasting stations.

The army announced that martial law would be strictly enforced and schools and universities were closed.

In his speech, the shah seemed to make the surprising admission that political excesses had occurred during his rule of Iran, and acknowledged that they could occur again.

"I am aware of the possibility that past mistakes and oppressions will be repeated, where some people might feel in the name of national reform . . . that the unholy alliance of financial and political corruption may be repeated," the monarch said.

"But I promise that past mistakes, oppression and corruption won't be repeated. Also, mistakes will be remedied."

While the often ignored constitution of Iran requires that new elections be held 90 days after the disolution of a government, the shah said instead that the elections will be held when order is restored. Until then, he said, "the maintenance of law and order is the main responsibility of the imperial armed forces."

Government officials went to great lengths to dispel the notion that the army had staged a coup, and the appearance of several civilians in the new Cabinet appeared to be an attempt to demonstrate that the shah himself had named the new government. Nine of the 12 ministerial port-folios were filled by generals, however.

(In Washington, a State Department spokeswoman said: "We support the shah in his decision. The shah moved to appoint a military government under his authority when it became apparent that another civilian government could not be formed to restore the public order essential to moving towards elections.")

The army swept through Tehran and quickly restored order in areas where rampaging youths had created chaos with a wave of arson and rioting over the past two days.

The streets were almost deserted yesterday, and in the few cases when demonstrations began, army troops opened fire with automatic weapons over the heads of protestors to disperse them.

The only newspaper published yesterday was a journal of Rastakhiz, the foundring political organization that the shah once envisioned as Iran's only political party.

The remaining newspapers were ordored to shut down. Employes said armed SAVAK agents entered the Tehran Journal, an English language newspaper, and ordered the employes to remain at their desks while the agents impounded the morning's editions. Ten journalists representing several newspapers were reported arrested during the day.

The ramy announced that martial law, which has been in effect since Sept. 8, would be enforced to the letter. It said persons violating the 9 p.m. curfew or prohibitions against more than two people congregating would be warned once and then shot if they failed to heed the warning.

All schools and universities were closed for the rest of the week, and the new Cabinet announced after a four-hour meeting that the government's first program will be to maintain law and order, ensure national security and provide essential public needs.

The government announced that the opening session of the Majlis (parliament), scheduled for today had been postponed indefinitely.

The new prime minister received his command training at the U.S. Army general Staff Colleg at Fort Leavenworth, Kan. and also received military police training in the United States.

He replaced as prime minster Jaafar Sharif-Emamimi, who was installed by the shah after the "black Friday" rebellion Sept. 8 in Tehran which left hundreds of antishah demonstrators dead.

Generals were appointed to all key Cabinet posts, leaving several civilian deputy ministers as heads of lesser ministries.

Gen. Gholam, Oveisi, the martial law administrator, was named to head the Labor Ministry. Oveisi, who played a key role in suppressing a Moslem uprising in 1963, will be charged with bringing to an end the crippling strike by oil workers which has threatened to ruin Iran's economy.

Civilians were named to head the ministries of foreign affairs, mines army, navy and air force, are in firm control of the government, at least until - or if - new elections are held.

Much of the shah's opposition appeared to go underground last night, with Karim Sanjabi, head of the Iranian National front reportedly remaining in Paris where he has been meeting with Shiite Moslem leader Ayatollah Ruhollah Khomeini. Other opposition leaders were keeping a low profile.

One National Front official said he expected to be arrested, but added that he doubted he or other activists would be detained for long, because the new government is probably eager to gain the confidence of the people.

The opposition leader added that "the only thing the people in the new government have in common is that they are trusted by the shah." He said he expected the government, headed by generals with no political experience, to collapse as economic chaos grows.

He also said there may be a wave of sabotage in the oilfields and refineries, and guerilla activity by radical groups.

In a statement, the National Front called the new government "crime agaisnt Iran," and said the only solution to the political turmoil here is a government formed by the opposition, with the removal of the shah.

The National Front, however, has not yet come to terms with Khomeini and his traditionalist Moslem supporters, who are seeking an "Islamic socialists republic" without the shah.

Meanwhile, strikes continued yesterday, although Iran Iair airlines announced that it had settled its labor problems and would resume flights.

Filling stations were still on strike in support of the striking oil workers, and long lines of motorists were backed up at gasoline stations as army tankers attempted to deliver fuel.

In his speech, the shah referred to the strikes, saying many "were justified." But he warned that "disroder and rebellion reached such stages that it constituted a menance to the economy."

The shah also made a conciliatory gesture toward Moslem leaders, calling upon "leaders of Islam and especially Shiites to try to help by inviting people to keep calm to preserve this only country that is Shiite."

By some accounts, the shah has gradually come to realize that he could reign as monarch in Iran, but that he cannot rule in the same single-handed manner he has for a quarter of a century.

Former prime minister Ali Amini, who has been mentioned as a possible premier in a succession government, and who met with the shah last week, said yesterday the monarch has become increasingly isolated and ill-informed by his palace advisers and did not know the extent of the rebellion until the very end.

"He really wants to do something like that [guarantee free elections and a democratic government], but his majesty first must have some guarantees from the people and the people must have some guarantees from the shah," Amini said in an interview in his suburban Tehran home.

"He has changed. He has gotten old already. He sees something wrong in this country. He wants to go give power to his son and create a transition in the government, too. But he has to have a guarantee that the government won't take away his reign," Amini said.

Amini said he believes the shah is resigned to the fact that "he can reign over a constitutional monarchy but not govern at the same time like he has before."

"He has reached this decision little by little," Amini said, adding that the events of the last few weeks made the shah's decision to seek a provisional government inevitable.

But many political observers here were wondering last night how trans-whether martial law would become institutionalized as it has in the Philliitional the military rule would be, and pines and other countries.