President Abol Hassan Bani-Sadr suggested today that U.S. congressional hearings into alleged American interference in Iranian domestic affairs could accelerate the otherwise "slow" process of freeing the estimated 50 Americans held hostage here since Nov. 4.

In an interview, the president also said he "personally" favors an Iranian government commitment to spare the life of the deposed shah, Mohammad Reza Pahlavi, if that were the price to pay for his extradition.

Panama -- where the shah has resided for the past three months -- forbids extradition for anyone facing the death sentence.

Despite the departure Tuesday of the U.N. investigative commission after it failed to secure permission from the militants holding the embassy to visit the hostages, Bani-Sadr has reiterated his month-old determination to solve the problem.

He said his motivation was not to please "President Carter, the American government or anyone else," but said settlement could have a beneficial effect "for a policy of independence for Iran."

He blamed a changing majority within the ruling Revolutionary Council for going back on its unanimous decision to allow the commission to visit the hostages.

He said he considered the Moslem students' continuing occupation of the U.S. Embassy as a "point of weakness." He pledged, "I shall continue my efforts to resolve all [other] centers of decision-making including that one."

He considerably softened his earlier suggestion that the pro-Moscow Tudeh (Communist) Party and the Marxist-Leninist Fedayeen have manipulated the militants inside the embassy in order to isolate Iran internationally and prevent it from opposing the Soviet invasion of Afghanistan.

Meanwhile, Iranian Foreign Minister Sadegh Ghotbzadeh said the upcoming parliamentary elections will allow the government to "dominate the power in the streets" and solve the hostage issue "quite quickly," Associated Press reported. In a radio interview monitored in Paris, Ghotbzadeh said he believed Iranians were losing patience with the militants holding the Americans.

["Time is working against the students," he said. "The people were entirely with them before. Today that is no longer the case."]

Speaking in fluent French in what has been the prime minister's office under the shah, Bani-Sadr said the kind of congressional hearing he envisaged would "study the State Depart- [TEXT OMITTED FROM SOURCE] and Pentagon roles," in Iran since 1953.

Documents should be provided by the United States and Iranian governments, but would not include those seized at the U.S. Embassy here and in part made public by the students, he said.

During his three-week tenure as foreign minister immediately after the embassy's seizure, Bani-Sadr endorsed the congressional hearing process suggested then by visiting Rep. George Hansen (R-Idaho).

In the back of Bani-Sadr's mind, then and apparently now, was the hope that such hearings by the legislative branch would relieve the White House from making the kind of public admission of American interference in Iran's internal affairs that he feels is necessary to clear the air between the two countries.

In November, the Carter administration moved decisively to block a plan by Hansen and Rep. Henry Reuss (D-Wis.) to have the House Banking Committee investigate alleged American financial misconduct in Iran.

Bani-sadr explained that the simplest way to solve the crisis remains the shah's extradition from Panama.

"Another and more difficult method," which he said would be a "long" process, involves assuring Iranians that "the American people understood that in the past the American administration had governed Iran through the shah's regime."

Once Iranians have been thus reassured, he said, Iranian public opinion will understand that "our struggle against foreign domination does not require seizing the embassy hostages."

"That will settle things," he added, "but it will be long."

He once again indicated that little progress on the hostages could be exected before the end of April, when the parliament is expected to consider the issue. Spiritual leader Ayatollah Ruhollah Khomeini's doused hopes of an earlier settlement 2 1/2 weeks ago when he directed the parliament to settle the crisis.

Hammering home the necessity of American "self-criticism," Bani-Sadr said that in November as foreign minister he believed the press could prove "the most effective way" to convince the American people to persuade the administration to make the gesture.

Explaining his personal view that the Iranian government should spare the shah's life, he said "the essential purpose of extradition is not to execute the shah. It is to give our people confidence and to allow confidence that in the future no one will play the role of servant of foreign powers who want to dominate the country."

Turning to the militants, the Communists and leftists, Bani-Sadr said the United States could blame only itself because its past behavior had left behind anti-American sentiment.

"Each of these groups is working for its own goals," he said about the Communists and leftists. "All this makes the situation more confused."

But he rebuffed suggestions that it was their influence that dictated the militants' intransigent refusal to allow the U.N. commission to visit the hostages or allow their transfer to governmental authority.

"On the contrary," he added, "so few people showed up [in demonstrations outside the embasy last weekend], just Tudeh and Fedayeen. We could see them because they were so few."

"The very fact that the communist demonstrators were unable to stage a larger protest, he argued, amounted to "a revolution in the public opinion."

Asked if the leftists and Communists were manipulating the captors, the president replied, "We do not yet have, unhappily, a strong enough intelligence service to investigate and know exactly what happened. But staging demonstrations outside the embassy does not constitute manipulation inside the embassy."