A leading Iranian diplomat warns that Iran may have to carry the war across the border into Iraq if Iraq fails to meet its conditions for peace.
But in an interview with the Monitor, Saeed Rajaie-Khorasani, Iran's ambassador to the United Nations, also said that his nation does not intend to occupy Iraqi territory and that it does not intend to threaten other nations in the region.
In a speech in Chicago on May 26, United States Secretary of State Alexander M. Haig Jr. declared that there is a ''great risk'' that the Iraq-Iran conflict may spill over into neighboring states and lead to changes in the regional balance of power. He said this would offer the Soviet Union an opportunity to enlarge its influence.
Reagan administration officials have been expressing the fear that Iran's recent victories over Iraq would lead to Iranian subversion of other oil-producing nations in the region, including Saudi Arabia.
''That is absolute nonsense,'' said Dr. Rajaie. ''We are no threat to anyone.''
The Iranian diplomat contended that the greatest threat to the region comes from Israel and from the United States. He denies reports that the Soviet Union or its Iranian proxies were gaining influence in Iran.
Dr. Rajaie listed a tough set of conditions for peace with Iraq, including war reparations which could come to hundreds of millions of dollars. He said those responsible for the war, including Iraq's President Saddam Hussein, would have to be brought to trial by an Islamic jury. More than 100,000 Shia Muslim Iraqis, expelled from Iraq, would have to be permitted to return to that country. Iraq would have to withdraw its military forces more than 30 miles from the border - out of artillery range of the border - so that the reconstruction of damaged Iranian cities and villages near the border could begin.
The ambassador also said that Iraq, through its invasion of Iran, has destroyed the Algiers agreements of 1975 on access to the Shatt al Arab waterway and, therefore, will not be permitted use of that waterway at the end of the war.
Dr. Rajaie, a former university chancellor, was a close aide to Iran's Prime Minister Mir Hossein Musavi when Musavi served as foreign minister. Rajaie is, therefore, believed to speak with considerable authority. Until now, Iran seemed to be giving conflicting signals as to whether it would push across the border into Iraq. But Rajaie's statement on the subject appears clear - indeed the clearest statement on the subject to date.
''I think we have already gone across the border several times now,'' Rajaie said. ''We are not going to occupy Iraq. . . . Iraqi citizens are entitled to their homeland just as we are entitled to our homeland.''
''We don't want to occupy anyone,'' he continued, ''but to pressurize the regime in order to get our rights, we might cross the border.''
At another point in the interview, in reference to a question about crossing the border into Iraq, Rajaie said: ''I would like you to think of this issue by putting yourself in our shoes. . . . Consider a situation in which a foreign enemy has come and occupied a part of the United States. And then you have been successful enough to expel the enemy from your own land. Then as soon as the enemy goes to the other side of the border, do you just smile and say goodbye? It would definitely not be the end of the argument. That would be quite illogical.''
Asked about reports of Soviet and North Korean assistance to Iran, Rajaie said simply that Iran had captured enormous quantities of Soviet war material from the Iraqis. He said he could not comment on a recent report that Syria had supplied Iran with shipments of Soviet military equipment which had originally gone to Syria. He denied reports that Israel had aided Iran.
''There is no Soviet adviser in Iran, and we have no support from Russia,'' the ambassador said. ''Fortunately, we have access to plenty of Russian tanks, and lorries, and machine guns . . . and all sorts of military hardware captured from the Iraqis.''
Rajaie said that there was also no truth to reports that the pro-Soviet Tudeh Party had been infiltrating the Iranian government.
''The Tudeh Party is a communist party,'' he said. ''A party based on the ideology of communism is definitely contrary to the principles of Islam.''
He said that the Tudeh Party had been discredited after being invited to explain its programs in encounters on televised panel discussion programs in Iran.
Rajaie said that he could not yet place a price tag on the war damage for which Iran is demanding reparations from Iraq. But he noted that Iran's oil industry had suffered devastating blows. The Abadan refinery, one of the world's largest, was destroyed, he said. A huge petrochemical complex suffered heavy damage.