Iran is enjoying its first moderately free press in a quarter century and even SAVAK, the dreaded secret police not used to tolerating criticism, sees the advantages.

Put simply, the establishment from Shah Mohammad Reza Pahlavi on down appears to prefer opposition in the press and parliament to opposition in the street.

A high SAVAK official privately confided that "anything" in the Iranian press these days was preferable to rumors - "They are our worst enemies."

By that he meant that such is the Iranian public's suspicion of the government that officialdom is blamed for everthing - including the Tabas earthquake in which more than 15,000 were killed last September.

Thus despite martial law, which in theory authorizes press censorship, Prime Minister Jaafar Sharifemami two weeks ago imposed his superior political logic on more literal minded Gen. Ghomal Ali Oveissi, the martial law enforcer.

The general sent censors into the principal Tenran dailies. He thus set off a rare event, a strike involving journalists, typesetters and all other staffers. But the prime minister's firm intervention won the day and as the English-language newspaper Tehran Journal remarked this papers' ability "to print what we want to say without let or hindrance - it sounds too good to be true."

"The country's press enjoys a minimal reputation for objectivity," the editorial admitted, "and people came not to trust what the press says and rumor mills flourish."

In further breastbeating, the Journal said, "Had there been a free press over the years would we only now have discovered how much corruption was going on in our midst our just how much discontent was felt by people?"

The Tenran papers have been making up for lost time. Favorite targets are the rich and powerful now under investigation for corruption and embezzlement. Many have fled the country.

So far the Shah - and his immediate family and their retainers - have been spared. But editors claim the imperial family's turn is coming while noting most of its prominent members are aboard.

In the name of respecting "national interest," editors agreed during the recent showdown to continue avoiding certain taboo subjects. They include the banned Tudeh or Iranian Communist Party, demonstrators' slogans such as "Down with - and death to the Shah" or criticism of the Shah himself or the military.

But Kazem Zarnegar, editor of the English-language newspaper Kayhan International, thinks that "providing we exercise caution and avoid calling for violence press freedom will respecd.

Twice banished from the newsroom by government Diktat in the 1960s, Zarnegar recalled the bad old days.

"We couldn't say how many Chieftain tanks the army had, or even mention the visit of the American or Indian chiefs of staff or that Iran had the world's largest hovercraft navy,"

"He minister of information used to "The minister of information used to call regularly to say what could and couldn't appear and on what page and with what sixe headline," he added. "The prime minister and other ministers used to call up at 5 o'clock in the morning and about 'Why did you write this?'"

Zarnegar is as surprised as anyone that such an establishment figure as Sharif Emai has turned out to be so tolerant in lght of his past - president of the senate, head of the much criticized Pahlavi Foundation accused of siphoning off millions of dollars, membership on about 50 boards of directors.

"But I haven't received a single telephone call since he took power," the editor said.

Even martial law, which interrupted a 12-day "spring" of uncensored newspapering in late summer, was soon gotten-round as editors began testing the water.

"We gradually just started writing more and more," Zarnegar explained.

In the process Kayhan, the Persian-language best selling daily, more than doubled its circulation - from between 350,000 and 380,000 daily to between 700,000 and 800,000.

Circulation went over a million in August when for the first time Kayhan dared print a four column front meini, th eexiled Shiiite Moslem leader who was spearhead much of the opposition to the Shah during the past 10 turbulent months.

Copies of that issue sold for $2.50. Even the government-run radio and television network has gotten into the swing of things, mixing news of the Shah with coverage of demonstrations and other opposition doings.

However, it took the prime minister's expression of amazement at the network's originally tepid coverage to uncover a martial law directive banning news of strikes and demonstrations.

He promptly issued orders ending that state of affairs and warned, "If you do not report such events the BBC [British Broadcasting Corp which has an extensive Persian language service] will."

So far the only voice raised against press freedom has come from the press itself.

Shocked by the sudden flood of accusations, sometimes unsubstantiated, Tehran Journal columnist Chris Powell warned of the dangers of witch hunts.

"Power struggles are always a bit lopsided and the lure of unlimited freedom to write what you want when you want and about whom you want can lead to all manner of abuses," she wrote recently. "Perhaps Iranian journalists need time to understand liberalization does not mean "libelization,'" she said.