Embittered and increasingly frustrated by Iran's refusal to make peace after seven months of fighting, Iraq has widened its initial war aims and now it will seek dismemberment of strife-torn Iran.

"If Iran continues to be an enemy, it is better to have five Irans, five small Irans rather than one big Iran," Tariq Aziz, a leading member of Iraq's Revolutionary Command Council, said in explaining this ominous shift in policy.

"We have reached the point where objectives have changed," he said in a two-hour interview here last week.

Aziz contended that the Iraqi decision to seek disintegration of politically troubled Iran -- primarily through supporting dissident minorities in that country -- was essentially a "defensive policy" stemming from Iranian intransigence. He said Iraq had hoped at the start of the war to make peace with a "united Iran."

Aziz's comments highlighted the imminent danger of a major escalation and change in the direction of a war that began in September as an Iraqi bid to force Iran to recognize Iraqi sovereignty over the vital Shatt-al-Arab, the waterway separating the Persian Gulf's two strongest military powers.

Seated in his book-lined office overlooking the Tigris River, Aziz explained his government's hardening attitude toward Iran and the war and discussed the state of Iraq's relations with the Soviet Union and the United States. Despite Moscow's refusal to provide Soviet-equipped Iraq with arms and its official stance of neutrality in the war, Baghdad will not cancel its nine-year-old treaty of friendship and cooperation with the Soviet Union, Aziz said.

"We are not irritated with the Soviet Union," he said, although he indicated that the two countries had narrowly avoided a major blowup.

On the other hand, despite some improvement in Iraqi-American relations, he said he was "not very optimistic" that the Reagan administration would cary out any "dramatic changes" in U.S. Middle East policy that would make possible a renewal of diplomatic ties broken off by Iraq 14 years ago.

Iraq, he said, nonetheless favored more high-level contacts between the two governments. His remarks came five days after Morris Draper, U.S. deputy assistant secretary of state for Middle East affairs, had talks here with high-level Iraqi officials, the first in nearly four years.

He warned, however, that if the Reagan administration makes another "mistake" such as the Camp David peace accords sponsored by the previous administration, "there will be a dramatic and very bad development in Arab-American relations."

In discussing the war with Iran Aziz emphasized that he saw no early end to the fighting. After three months of heavy fighting, the war reached a stalemate and has been in a lull, partly because of heavy winter rains but partly, too, Iraq says, beacause it wanted to give time to so far unsuccessful outside diplomatic efforts to bring Iran to the negotiating table.

Iraq claims to have seized 6,000 to 8,000 square miles of Iran's oil heartland, Khuzestan, but the Iraqis still have not gained total military control over the Shatt-al-Arab, their lifeline to the Persian Gulf. Now, there is talk of a new spring offensive by Iraq and much speculation here about what its objectives will be.

Aziz, who is also a deputy prime minister and a major figure in the ruling Arab Socialist Baath Party, said despite the fact that recent U.N., Islamic and nonaligned peace efforts had created an atmosphere "for the possibility of discussing peace," Baghdad had detected no real willingness among Iranian leaders to accept a negotiated settlement to the centuries-old dispute over the Shatt-al-Arab.

He said the Iranians were living on false hopes of a military victory and erroneous information being fed to them by the Syrians about the political situation in Iraq, leading them to believe they could hold out longer than the Iraqis.

Asked about a possible new offensive to pressure Iran into holding talks, Aziz said the Iraqi government did not want to endanger mediation efforts yet.

"But if the peace process fails, then the language of guns will prevail," he added.

He gave no hint how long Iraq would wait before launching a new offensive but said nothing to suggest that such an action was imminent. Western diplomats here assume, however, that an offensive is likely to be launched before the scorching heat of summer.

The first indication of shifting Iraq war objectives came in midi-March, when President Saddam Hussein suggested in a speech that Iran deserved to be dismembered because of its intransigent attitude. Earlier, he said Iraq openly would provide military and political aid to Iranian minority groups such as the Kurds and Arabs in their struggle for autonomy against the Islamic government of Ayatollah Ruhollah Khomeini.

"Until the president spoke, our strategy was to deal with a united Iran only. We didn't give promises to the other [opposition] sides in Iran," Aziz explained. "But now we don't care if Iran is dismembered. . . . This means there is a change in our policy toward the war."

"The more the war continues, the price Iran should pay would be higher," he said.

Aziz said Iraq would limit its compaign to bring about the dismemberment of Iran to aiding the Iranian minorities in their struggle against Khomeini. "We are not going to send our Army to Azerbaijan in order to achieve the independence of Azerbaijan," he said.

Iraq has, however, sent its forces across the border into Iranian Kurdestan and is assisting Kurds there in a struggle against the Iranian Army. It is also helping the Arabs in the areas occupied by Iraqi forces in Iran's Khuzestan Province to press their demands for autonomy. Whether Iraq is in a strong enough position militarily to provoke the dismemberment of Iran as a nation, even through stepped-up assistance to the Iranian minorities is not clear.

Aziz gave the impression that while the Iraqi leadership did not care if Iran falls apart, it did not believe this was in either nation's best interest. At one point, he went out of his way to deny that Iraq was an "imperialist" country or "part of any international strategy," adding "what interest would we gain from the dismemberment of Iran?"

Speaking about Iraq's present relations with Moscow and Washington, Aziz outlined for the first time since the war began Iraq's attitude toward the Soviet Union. He said a major crisis in Iraqi-Soviet relations because of Moscow's refusal to provide arms or spare parts had been avoided mainly because Iraq had succeeded in getting them elsewhere.

"If we had failed to do that, we might have become irritated, very hostile, very hysterical against the Soviet Union," which he said would have been a mistake.

"A leadership should be balanced in its foreign relations. You don't have to jump from one side to another," he continued. "Now we can behave serenely with the Soviet Union without being hostile to them."

Iraq saw no reason to cancel its friendship and cooperation treaty with the Soviet Union, he said, noting that there had been no "legal obligation" requiring Moscow to come to its assistance in the war.

Regarding Iraqi-American relations, Aziz noted several areas where he said he saw an improvement, including a change in the previous U.S. perception of Iraq as a "pro-Soviet" nation.

"We are friends with the Soviet Union; we don't pretend the contrary. But our policy is not dictated from Moscow," he said. "This is understood by America. This is very good."

Also, he added, the Iraqi government had no evidence that the United States was involved in any "conspiracies" against it today, such as in the early 1970s, when the Central Intelligence Agency provided aid to the Kurdish rebellion in the north.

On the central issue that led to the freeze in relations between the two governments -- U.S. support for Israel and its failure to solve the Palestinian question -- Aziz was pessimistic.

"Everybody is saying not before the middle of this year is the American administration going to specify its policy," he said."I will tell you. We are not very optimistic. We don't expect any dramatic changes. But we will see."

Aziz did not indicate what kind of change would be necessary to satisfy Iraq in order for diplomatic relations to be restored, limiting himself to saying simply that "any change in the American attitude toward the Arab-Israeli conflict bringing America to a more balanced attitude toward this conflict will help in developing relations."