The Ethiopian government called an Israeli-organized airlift of thousands of Jews out of Ethiopia a "sinister operation" today and protested what it called "this gross interference" in its internal affairs.

A Foreign Ministry statement released in Addis Ababa said Ethiopia was not involved in the airlift and condemned neighboring Sudan and other countries for what it called "illegal trafficking" in Ethiopian citizens, news agencies reported.

The airlift, which has just become public in Israel, is the climax of a 10-year-long, highly secret "underground railroad" operation to rescue them from the turmoil of the Ethiopian revolution.

While the full dimensions of the airlift are still not clear, it appears that the Israeli government is attempting to transport almost the entire remaining community of Ethiopian Jews out of that country after years of being accused by their sympathizers in Israel and the United States of not doing enough to help them.

According to news agency reports from Brussels, the Israeli government hired a Belgian charter company, Trans European Airways, to carry out the airlift through Sudan, Ethiopia's western neighbor.

Daily flights of Boeing 707s have been shuttling the Falashas, as the Ethiopian Jews are called, from the Sudanese capital of Khartoum to a number of European cities such as Rome, Basel and Brussels, from where they have been taken on to Israel, according to these reports.

The Belgian government said Friday that Trans European Airways has ferried 7,000 Ethiopians on about 35 flights to Israel since November, The Associated Press reported.

Such an operation could not possibly have been carried out without the knowledge of the Sudanese government, and it is likely that the United States played a role in persuading it to allow the airlift to take place through Khartoum.

Sudan, unlike Egypt, has no diplomatic relations with Israel and apparently insisted that the Falashas be taken first to Europe before being flown on to Israel.

Press and radio reports estimate that between 10,000 and 20,000 Falashas already have been airlifted or are awaiting transport, which is about the total number of these people believed to be living inside Ethiopia.

Ever since the military ouster of the late emperor Haile Selassie in September 1974, the Israeli government quietly has been smuggling the Falashas out of Ethiopia either through Sudan or Kenya.

Mostly it was done in small groups, a single family or one individual at a time, with a maximum of secrecy to avoid upsetting the Ethiopian authorities.

The trip out, particularly across Ethiopia to the Kenyan border, involved a long trek and many hazards including passage through areas of the country being ravaged by drought, famine and civil war.

Western correspondents based in Nairobi and other African capitals picked up reports about this "underground railroad" from a wide variety of western and Israeli diplomatic sources and private voluntary organizations starting in the mid-1970s.

But Israeli diplomats in particular asked that the project not be publicized.

Thus, it is particularly ironic that the secrecy long surrounding the whole operation should have been ended by a leak to an Israeli newspaper by a top Israeli immigration official.

For those aware of the secret Israeli operation, like this reporter, it was never clear whether the Ethiopian government really cared about the exodus or was simply turning a blind eye, possibly in exchange for Israeli-provided spare parts for a squadron of American-made F5Es Ethiopia had obtained just at the start of the long political upheaval and before the sharp deterioration in U.S.-Ethiopian relations in 1977.

The Ethiopian revolution since its onset has seen hundreds of thousands of peasants displaced or forced to flee into Sudan, Kenya or Djibouti either in search of food, refuge from the civil war or exile.

The Addis Ababa government has never seriously protested to neighboring states about their reception of these refugees or even a program in the early 1980s to resettle some of them in the United States.

On the other hand, it did support a U.N.-backed program of peaceful repatriation of some refugees living in Djibouti and Sudan willing to return to Ethiopia.

So far, it has had only limited success.

The Falashas, numbering between 20,000 and 30,000 and settled in a region particularly hard-hit by civil war around Gondar in northwestern Ethiopia, seemed in many ways to be just one more refugee group seeking to escape the ravages of war and later famine.

Potters by trade, a lower-class occupation in Ethiopian society, the Falashas long have been dirt poor and lived in isolated villages often in terrible conditions.

Their sympathizers in Israel and the United States said that they traditionally have been dealt with unfairly and that the military government in Addis Ababa has been discriminating against and even persecuting them.

However, to anyone familiar with the conditions of Ethiopia -- the extreme poverty afflicting much of the population -- and the central government's inability since 1974 to establish control over much of the northern area of the country, the charge of deliberate persecution seems off the mark.

It is true that the Falashas live in a region where both leftist and rightist opponents of the Addis Ababa government have had their strongholds and where many battles were fought.

But there has never been any evidence that the Falashas were politically involved in the struggle either for or against the government.

For years, the Israeli government has been under mounting pressure from a pro-Falasha lobby inside Israel and in the United States to take more decisive action to "save" the Falashas from extinction.

While the underground railroad functioned intermittently, it had failed to date to bring any significant number back to Israel, according to these sympathizers.

The recent drought in Ethiopia, which again has sent hundreds of thousands of peasants fleeing in all directions for food and shelter, has provided Israel with a perfect reason for a massive airlift.

The objective of this operation, which apparently began several months ago, appears to be no less than the transfer of virtually the entire remaining Falasha community from Ethiopia to Israel.

Why Cairo was not used as a transit point for the airlift remains unclear.

It is closer to Tel Aviv than any European capital and there are already many flights, including those of the Israeli airline, between here and Israel.

Apparently the Egyptian government decided not to get involved even indirectly in the politically sensitive operation, possibly to avoid highlighting its ties with Israel at a time when it is working to restore its diplomatic relations with other Arab capitals.