The political upheaval in Iran has resulted in a major increase in heroin smuggling to Washington and other major U.S. cities, according to law enforcement officials and other authorities.

The end result, especially noticeable in the Washington area, has been more, higher quality herion available for sale to addicts, the officials said.

Law enforcement officers attributed the recent increase in smuggling activities from the Iran to the easy accessibility to herion there and the ability of smugglers to leave that country unchecked because of political turmoil.

"The word on the street is a lot of it [herion] is Iranian," said Kurt Brandt, medical director of the District's substance abuse administration, who regularly interviews heroin addicts as they seek addiction treatment.

"It's really starting to overwhelm us," said special agent-in-charge David G. Canaday of the federal Drug Enforcement Administration, whose agency was involved Wednesday in the seizure of seven pounds of uncut Iranian herion here.

Statistics that are used as indicators of increased heroin availability were up sharply in the last quarter of 1979, and that trend continued last month, officials said.

For example, the number of persons who died from heroin overdoses last year was 34, the most in one year since 1971. Fifteen of last year's heroin overdose deaths occured in the first six months of the year, 19 in the last six months, and D.C. medical examiner James L. Luke said, "It's continuing apace in the current year."

Shifts in trends in the underworld for the heroin trade are not unusual here. For a while, most of the heroin coming into the city was often impure brown Mexican heroin. Then the market shifted to Southeast Asia and now, most heroin seems to be coming from Iran, officials said.

Several law enforcement officials expressed particular alarm at two aspects involving the increased smuggling of Iranian heroin.

First, the heroin is of unusually high quality -- 90 percent pure or more -- and is being sold by enterprising persons reportedly taking advantage of Iranian political turmoil to quickly move the drugs to the United States, where they can make one-time, high-profit, quick-turnover deals with established drug distributors.

Second, the officials report they are "hamstrung" in attempting to control the drugs at the sources because of the political situation there. There is no U.S. drug enforcement liaison machinery in Iran now, officials said, and "there's so much chaos and confusion there, it is easier for a smuggler to get the stuff out now than ever," one added.

Another drug investigator said most of those being targeted as a part of a continuing investigation into the Iranian drug smuggling increase previously were small-time smugglers.

"They see a good thing, and they are out for quick money," the investigator said. He said there is an amateurish quality to some of the alleged drug deals being made -- despite their size -- such as the sellers giving half-pound free samples to prospective buyers and the sellers not diluting the heroin before they sell it.

Although there has been no panic on the streets here for heroin in recent years, undercover agents and drug informants say there is a clear upswing in both the amounts and the purity level in drugs taken from addicts charged with crimes.

Drug officials said the narcotics can be traced to Iran by laboratory tests that search for certain characteristics in the drug samples.

Robert A. Keyes, head of the D.C. substance abuse administration, said Iranian heroin had reached England last summer and officials there were anticipating its arrival in the United States soon. "It's here now," Keyes added.

In addition, Gen. Hassan Jeru-Ahmed, commander of the Blackman's Development Center, which operates a third-party bail custody program for criminal defendants in D.C. Superior Court, said there is "talk of Iranian heroin on the streets . . . I'm seeing more heroin cases coming through the courts."

Keyes and some law enforcement officials cautioned that heroin here continues to come from other countries, but noted as well that the influx of Iranian heroin has coincided to some extent with a sharp decline in the availability of "Mexican mud," as less pure Mexican heroin is known here.

City narcotics treatment officials gave these additional statistical indicators of increased heroin on the streets:

Total admissions to city run treatment centers for heroin addicts are up from 2,239 in 1978 to 2,849 in 1979, with admission running heavier in the second half of 1979 than in the first half.

"New" admissions -- addicts seeking treatment for the first time -- increased from 682 in 1978 to 897 in 1979, with an unusually strong surge in the second half of 1979.

The percentage of criminal defendants arraigned in Superior Court with traces of heroin in their urine jumped from 9 percent in the first half of 1979 to 11 percent in the second half. This contrasts with an over-all annual rate in 1978 of 8.5 percent.

In addition to the 34 overdose deaths in 1979, there were 153 heroin-related cases reported at Washington area hospital emergency rooms during the first half of 1979. There were only 204 episodes in all of 1978, and the second-half figures of 1979 have not been compiled.

D.C. police figures show that reported burglaries and larcenies -- the crimes most commonly committed by heroin addicts to support their habits -- increased substantially in the first three quarters of 1979 over the same period in 1978. Figures for the fourth quarter in 1979 were not available, but police officials said the same upward trend is continuing.

Meanwhile yesterday, the three persons arrested in connection with the seven-pound drug seizure Wednesday remained in jail in Alexandria under high bonds.

At a bond reduction hearing for one of the defendants, Mohammed Roshan of Chevy Chase, the owner of the West End Restaurant in D.C., a federal magistrate refused a request that bond be lowered and Roshan be released in the custody of two friends -- one of them a former Central Intelligence Agency employee.

Assistant U.S. Atorney Nash Schott opposed the request, saying Roshan was a part of a "sophisticated group of individuals" who might flee the country if freed.

Schott said the alleged ringleader of the drug scheme, Sharokh Michael Bakhtiar of Hyattsville, had described himself to undercover agents as a first cousin to a former prime minister of Iran, but drug officials said yesterday they had been unable to confirm that information. The third person arrested was Reza Mianegaz of Springfield.