Soviets find their star is rapidly waning in Iran

The ruling mullahs in Iran have signaled fresh displeasure with their suitors in the Kremlin.

According to foreign diplomats here citing colleagues in Tehran, the Iranians recently refused formal agreement on the Kremlin's choice for a new Soviet ambassador. The Iranians were said to feel the candidate suggested was not of sufficiently high stature.

In mid-May, meanwhile, Iran's theocratic regime sat out a Kremlin-supported conference of world religious figures for nuclear disarmament.

A number of other Mideast states -- including the Iranian's chief Arab ally, Syria, and their battlefield foe, Iraq -- did send representatives to the parley.

Riding piggy-back on Iran's ''anti-imperialist'' overthrow of the former Shah , the Soviets have been bidding for closer ties with their southern neighbor.

But while economic relations have been widening, particularly since the Soviet's transport routes helped Iran dent the effects of Western trade sanctions during the US Embassy hostage crisis, the search for solid political entente has been a lot rougher.

''There's still no real government in Iran,'' lamented one Soviet official recently to a representative of an Arab state enjoying good relations with Moscow. ''And the Iranians don't trust us. They think we're in favor of some kind of communist takeover there.''

Earlier this year, a prominent Pravda commentator charged that despite improving economic ties -- a process including a record 1981 trade turnover and the start of small-scale Iranian oil exports to Moscow -- some ''right-leaning'' clerics around Ayatollah Khomeini were seeking to undermine over-all Soviet-Iranian relations.

The Pravda article said the Iranians had cut back the number of Soviet diplomats accredited in Tehran, closed a Soviet consulate near the Soviet-Iranian border, and refused entry visas for Soviet journalists.

A Persian-language broadcast by Moscow Radio added that a Soviet Muslim delegation that visited Iran earlier this year had been ''confronted by unfriendly attitudes toward...The Soviet Union on the part of some officials.''

Among issues on which the Iranians seem to be particularly ''unfriendly'' are the continued Soviet troop presence in neighboring Afghanistan, and the Kremlin's determined public neutrality in the Iran-Iraq conflict.

Diplomats here are assuming that the Kremlin candidate for a new ambassador in Tehran is, in keeping with neutrality, of about the same prominence as Viktor Minin, named as Soviet envoy to Iraq in March. He is a veteran Mideast specialist but of somewhat lesser rank than the current Soviet ambassador in Iran, Mikhail Vinogradov, a former deputy foreign minister. This would explain Iranian reluctance to agree to the Soviets' suggestion for Mr. Vinogradov's successor.

The Iranians' absence from the recent religious meeting in Moscow is being widely attributed to the fundamental distaste on the part of Tehran's fundamentalist clergy for the officially atheistic Soviet system. Although it is conceivable that the Soviets, grating at the treatment their own Muslim delegation got in Tehran, may simply not have invited any Iranians to the Moscow conference, Arab sources here say they understand an invitation was extended; and refused.

The Soviets, meanwhile, seem intent on pursuing what has become a carrot-and-stick approach toward political relations with Islamic Iran. This strategy involves taking consolation from -- and public cheering -- the fact that the Iranians still intend to talk a good deal more nastily of the ''greatly satanic'' Americans than of the Kremlin.

While hoping that expanding Soviet-Iranian economic ties will eventually spill over into the political arena, the Soviets have, in the past year or so, seized on everything from Iranian holidays to earthquakes to dispatch the appropriate good wishes, or condolences, to the Khomeini regime.

At the same time, the Soviets have, in effect, issued various reminders to the Iranian regime that it lives next door to a superpower. Early last year, the Soviets protested Iran's handling of a brief assault on Moscow's embassy there by Afghan exiles, serving notice that the Soviet Union might have to take measures to protect its own embassy if the Iranians proved incapable of doing so.

Since then the Soviet media have periodically upbraided Iranian officials or news outlets for perceived ''anti-Soviet''stands.