"It's pathetic. There must be close to 15 relief agencies here for every kind of refugee, but these people just fell through the cracks."

The "people" the young Austrian volunteer worker was talking about are 500 to 700 Russian Jews who emigrated to Israel in recent years, did not like it, and now want to return to the Soviet Union.

The Soviets, however, have not let them back in, and so these homeless people have been waiting - many of them for years -- scattered in run-down tenements in the two poorest sections of this Austrian capital. Many of them are unemployed or unemployable - too old to work, not able to speak the language, and not interested in integrating into another society.

"They are forgotten people," says a Western diplomat. "There is nobody to help them except the Austrians, who let them stay here and provide them welfare. But they are a growing problem even for the Austrians.

Israel basically will have nothing more to do with these people, explains a refugee worker. Similarly the several other Jewish aid organizations here are aimed at assisting Jews in getting from the Soviet Union to Israel, the United States, Canada or other Western countries.

"There is no organization that helps Jews - or wants to help Jews - to get to Russia," she says. "Only the Russians can do that."

Chancellor Bruno Kreisky, who was born a Jew, has privately taken Vienna's Jewish community to task for not helping these outcasts more.

Jewish relief officials, however, say that the would-be Soviet returnees do get help from some individual families and that special projects such as language courses have been set up. But as a group "they are an acknowledged political embarrassment," said one official.

"Why do you want to go back to the Soviet Union," we ask them!"Are you crazy?" said the relief official.

The Soviet Jews that wind up back here are only a small fraction of the ones who pass through on their way to new homelands. During 1973, for example, some 35,000 Soviet Jews arrived here on daily trains via Poland and Czechosolvakia. The vast majority of the emigrants went on to Israel and have stayed there.

But in the last two years, the Soviets have restricted the annual outflow to about 15,000, largely as a reaction, officials believe, to U.S. actions linking Soviet trade status to the Kremilin's emigration policies.

The Austrians, who feel that their role as neutrals willing to help refugees is best carried out without publicity, do not talk much about emigration, especially when it come to Soviet Jews.

Since 1974, however, the Austrians have quietly reduced the role of the Israelis here in shepherding people directly to Israel and are trying to insure free choice to those Soviet Jews who pass through Austria.

One result, sources say, is that slightly more than half the Soviet Jews now passing through here chose not to go to Israel.

Most of those who prefer to go elsewhere ask to go to the United States. These persons are then sent on special trains to Rome, where they await investigation and processing that usually takes three or four months.

Soviet Jews who chose Israel are taken to a special transit camp near Vienna's Schwechat airport and are usually out of Austria within a day.

Nobody knows with precision why many of the Jews coming out of Russia now are not choosing Israel. Officials here say recent emigrants seem to be coming more from Soviet urban areas than in the past and that an Israeli kibbutz may be less appealing than it was to rural Russians. The feeling that the situation in Israel is not as good now and the constant threat of attack may also play a part.

In addition, sources suggest that the pre-1974 period, when the Jewish agency was playing such a direct role - to the eventual annoyance of Kreisky - in handling the Soviet immigrants here, might have resulted in less than free choice for some Soviet Jews at that time.

As for those emigrants who left Russia and Israel and are now back here, one official says, "It is not a reflection on Israel or anyone else. In any movement you'll find some who don't work out, who can't adjust."

There years ago, sources say, only about 150 of these would-be returnees were here. Today, well-placed Austrian officials admit to quartering probably several hundred, though no one seems to have precise information.

For may, their Israeli passports have expired, and they are stateless except for an Austrian alien registration.

Occasionally, they stage sit-ins at the Soviet embassy, but the Soviets thus fare have not relented in letting the people back in, although one Austrian official says a few have quietly been allowed back.