TEHRAN--As thousands of protesters chanting "Death to the Shah!" marched peacefully through the streets of Tehran, the Iranian Parliament opened debate yesterday on whether to endorse the new civilian government of Prime Minister Shahpour Bakhtiar.

If Bakhtiar receives a vote of confidence, it is expected that the way will be clear for Shah Mohammad Reza Pahlevi to leave the country later this week.

Twenty-two of the 268 legislators of the Majlis, the lower house, spoke yesterday, half in favor of Bakhtiar's government and half against. The Majlis, which will not meet today, scheduled a vote of confidence for tomorrow. Debate in the Senate begins today.

Political observers said the new government would not receive automatic approval but both houses will probably give Bakhtiar the vote of confidence he needs to begin carrying out a program aimed at pulling Iran from the brink of economic collapse.

Ayatullah Khomeini, the exiled religious leader of Iran's dominant Shiite Moslem sect, said yesterday he will probably announce the establishment of an Islamic state in Iran in a few days.

Popular Acclaim

Khomeini said if his followers have the power, "and if the nation can get him," they will prevent the Shah's departure.

"We will not permit him to leave, and we will arrest him for his crimes, to be tried and punished," he said.

Because his countrymen have supported him through current demonstrations, they have proclaimed that he is their leader, Khomeini added.

Khomeini said he would not have any position in the future government but that he would supervise others. Asked if he would be, in effect, the strongman of Iran, he replied, "You may assume so."

Khomeini also said United States military bases "could not remain in Iran because they are contrary to Iranian independence" and refused to predict whether he would send armies against Israel in the event of another Mideast war.

The Puppeteers

If the United States stops supporting the Shah, he added, "then we do not have any opposition to the American people...and we will treat them with friendship and justice."

Khomeini made his remarks on the CBS television program, "Face the Nation." The interview took place in Fontchartrain, France, where he is in exile.