The head of Iran's revolutionary courts said today that the deposed shah and his family are considered to be under death sentences and that anyone who assassinates them would be "carrying out the people's verdict."

At the same time, Ayatollah Ruhollah Khomeini, the Iranian revolution's revered Islamic leader, decreed that only Iranians proven to have killed or to have issued orders for killing or torture resulting in death should be executed under his revolutionary justice, the government news agency Pars reported.

The combined effect of the two declarations was to underline the new government's determination to punish those responsible for repression under the shah while countering a negative image abroad created by the executions of more than 200 persons.

Addressing a news conference, court leader Ayatollah Sadegh Khalkhali said Western ideas of justice had no place in the Islamic revolutionary courts. The rotund ayatollah, who said he had been appointed to his post by Khomeini, named the imperial family members facing the death penalty as Shah Mohammad Reza Pahlavi; his wife, Empress Farah; his twin sister, Princess Ashraf; his brother, Prince Gholam Reza; and his mother-in-law, Farideh Diba.

Khalkhali also named the last two prime ministers of prerevolutionary Iran, Gen. Gholam Reza Azahri and Shahpour Bakhtiar, as candidates for Islamic firing squads. Others on the death list, he said, were the former Iranian ambassador to Washington, Ardeshir Zahedi; the former martial law administrator of Tehran, Gen. Gholam Ali Oveissi; and former Cabinet minister Hushang Nahavandi.

All are out of the country or in hiding. The shah and his immediate family are currently staying in the Bahamas.

Khalkhali said there was no need to try those on the list, since they had already been sentenced to death by Iranian public opinion.

He said anyone who tried to assassinate the shah anywhere in the world should not be considered a terrorist because he would only be carrying out of this verdict of the Iranian people.

Justifying the summary trials and executions of figures in the shah's governments, Khalkhali said, "Those who enter into war against God and his prophets and who try to spread corruption on earth must be killed or have their hands and feet cut off or be sent into exile."

He referred to the Koranic charges commonly cited in revolutionary court death sentences. The revolutionary courts have consistently used the term mofsede fel arz, or "corrupt of the earth," to characterize their victims. According to Moslem scriptures, such a person is not fit to live on the planet and must be eliminated.

Khomeini's decree, issued via the news agency from his headquarters in the holy city of Qom, seemed to represent an attempt to narrow the definition of capital crimes for the Islamic courts. After listing the conditions required for death sentences, it said:

"No court has the right to issue death sentences and no person should be executed except under the above two conditions."

The reining-in struck observers as an effort to mollify foreign critics of justice under the Islamic republic. It remained to be seen whether the decree would be observed throughout the country, but the ayatollah's word carries enormous weight and he is the new Iran's de facto chief of state.

"I think Khomeini wants to put an end to these kinds of executions," an Iranian official said. "But these days, one never knows how things will actually turn out."

If carried out, the order would end the threat of execution for many former government ministers and other pro-shah figures, such as millionaire businessmen. Last week two wealthy Iranian businessmen were executed for alleged crimes including "economic imperialism." One of them, Habib Elghanian a Jewish plastics magnate, also was charged with contributing financially to Israel, raising fears that other Iranian Jews would also face capital punishment under similar accusations.

Khalkhali said his press conference was to correct what he said were foreign misrepresentations of the work of the revolutionary courts. He explained that, for example, executions were carried out promptly after a verdict because it was against Islamic law to feed or give water to a condemned man.

He also said that lawyers were only permitted for defendants who were deaf and dumb. Otherwise, he said, they could defend themselves.

Provisions to the contrary, Khalkhali said, were based on Western models of justice and were in applicable to the Islamic revolutionary courts.

Speaking before Khomeini's new edict became known, Khalkhali said Khomeini had personally ordered him "not to listen to anybody," not even Khomeini himself, in judging defendants.

Denouncing foreign criticism of the trials, Khalkhali said, "to pity a sharp-toothed tiger is to oppress the sheep."

In sharp contrast to Khalkhali's statements - and more in line with Khomeini's - were the latest comments of Ayatollah Kazem Shariatmadari, the second most revered of Iran's senior Shiite Moslem leaders. In a Tehran newspaper interview published today, he called for an amnesty to apply to a large number of former officials under the old government.

Shariatmadari, regarded as the country's foremost Islamic scholar, criticized the trials, saying no one charged with interpreting Islamic law had the right to be tyrannical. He condemned the revolutionary character of the trials and said they should either be based strictly on Islamic law or in international standards of juris-prudence.