Secretary General Kurt Waldheim returned here today from Tehran saying he was "glad to be back, especially alive," and predicting "no quick solution" to the Iran crisis in the absence of a controlling government there.

In a news conference following his arrival, Waldheim described the chaotic administration in Iran as among the principal impediments to resolving the situation.

The ruling Revolutionary Council in Iran "isn't really a government," Waldheim said. Student militants holding American hostages in the U.S. Embassy "have their own administration and make their decisions independently."

Waldheim described little more than an expression of interest by the Revolutionary Council in his offer of a U.N. investigation of Iranian grievances against the deposed shah and the United States in exchnage for the freedom of the hostages.

"They are still reluctant to release the hostages," Waldheim told reporters on his airport arrival. He said he would present to the Security Council the invesigation proposal he had discussed with Iranian officials as an alternative to the shah's return to Tehran for trial.

But U.N. officials who traveled with Waldheim cautioned that there was no firm commitment by the Iranians to any of the ideas that the secretary general proposed.

More ominous, in the view of these officials, was the impression that no one, certainly not the Revolutionary Council and perhaps not even Ayatollah Ruhollah Khomeini, is in control of Iran now. "There is another power center," Waldheim said, "which is the students."

"But there is still an enormous animosity against the United States there," he added.

Immediately upon return, Waldheim said, he spoke by telephone with Secretary of State Cyrus Vance. Waldheim said he would report to the Security Council this weekend on his trip. The council voted last Monday to give Iran a week to release the hostages before it look up imposition of sanctions.

Waldheim also plunged into consultations with Security Council President Jacques Leprette of France on the mission to Iran and the request by more than 50 nations for a council debate on the Soviet invasion of Afghanistan.

The afghan debate, which members decided should begin Saturday, was requested yesterday by the United States and a wide range of nations.

Afghanistan sent a letter saying such a discussion would be "clear interference in our internal affairs." The new Afghan foreign minister, Shah Mohammed Dost, arrived for meetings with Waldhim and Leprette. Dost came from Moscow, where he met with Soviet Foreign Minister Andrei Gromyko.

The Soviet news agency Tass quoted Dost as saying the call for a council meeting "not only has nothing in common with the goal and tasks of the U.N. but directly contradicts them."

Just before Dost arrived Afghanistan's deputy U.N. representative, Abdul Hakim Tabibi, submitted his resignation because of the Soviet intervention in his country.

Tabibi appealed to "our traditional friends," the Soviet Union, to withdraw its forces quickly. If it does, "I'm sure Afghanistan and myself will always remain sincere friends of that country. Otherwise, they lose our friendship and the friendship and trust of others," he said.

Tabibi also warned that his countrymen throughout their turbulent history had defended their independence against all invaders -- from Alexander the Great and Genghis Khan to the British.

"True, our country is small and poor, but it also has never compromised its independence and identity," he said, also appealing for support from other countries.

Security Council meetings on Afghanistan are likely to run through the weekend and into next week to enable as many countries as possible to go on record against the Soviet incursions.

Several nonaligned nations have prepared a resolution that would not name the Soviets but would call for withdrawal of all foreign troops from Afghanistan.

There is no expectation that any resolutions condemning the Soviet action or calling for the withdrawal of its troops will escape a veto by Moscow, but Western diplomats hope that the exercise will bring home the breadth of international opposition to the invasion of a small, independent country.

U.S. officials indicated that despite the Afghanistan debate, they would press for a resumption Monday of the Security Council meetings on Iran to consider the imposition of sanctions.

The council acted on Dec. 31 to give Iran until Monday to free the hostages, and decided to act on that date to impose sanctions if there was no compliance.

But there were hints from U.S. officials that Washington might not press for the actual imposition of sanctions on Monday, and might allow more time for consultations on the details of a sanctions plan. There was no certainty that the United States had the nine votes necessary to impose sanctions even though 11 nations voted in favor of the Dec. 31 resolution.