TEL AVIV, July 19 - Michelita de los Reyes is a Catholic by faith, a maid by profession and a Filipina by citizenship. She also is part of a demographic phenomenon that could make Jews a minority in Israel by the end of the next decade.

A 37-year-old mother of three from the Philippines island of Palawan, Reyes mingles easily with the Thais, Chinese, Africans and eastern Europeans who gather Sundays at Tel Aviv's Central Bus Terminal to exchange grievances, job hunting tips and experiences.

They and thousands of other foreign workers not only give Tel Aviv a cosmopolitan look, they also are changing a nation whose Zionist founders hardly envisaged a demographic explosion of non-Jews.

The kibbutz and moshav farming communities of today's Israel rely almost entirely on foreign labor, a far cry from the days when working on the kibbutz was part of the Jewish pioneering spirit and kibbutzniks were considered members of the elite.

Today even middle-class Israelis can afford to hire a foreign housekeeper such as Reyes.

Ayoub Karaa, head of the Knesset Committee for Foreign Workers, estimates this foreign work force - two-thirds of whom, Reyes included, are unregistered - may already number as many as half a million, or 9 percent of Israel's population. Others put the figure at 300,000.

"I've been warning people without success that Jews in Israel will become a minority. It could happen by the year 2020. But this is too weird a concept for Israelis to accept," said Karaa, who is not Jewish.

Arnon Sofer, Israel's leading demographer, warns that foreign workers are "only the last straw" of what he calls "a catastrophe-in-the-making." Sofer says that of the 10 million inhabitants in Israel, the West Bank and the Gaza Strip, 5 million are Jews, 4 million Palestinians, 1 million Russians and as many as 300,000 foreign workers.

The influx of foreign labor is mainly due to 22 months of Israeli-Palestinian conflict. The Jewish government has banned 180,000 Palestinians from crossing from the territories to their jobs in Israel. Employers needed replacements - fast.

The door was open for economic migrants. They came in droves from eastern Europe and Asia looking for a better future.

Many, like Reyes, have already helped relatives and family members to come and work in Israel where they can earn about $1,000 a month, far more than the typical $100 a month back home.

Some observers say that if Jews become a minority in Israel, it would be a blow to the Zionist concept of building and defending a land whose main mission was to absorb Jews from the Diaspora.

Some 70 nations are now represented in Israel's foreign labor force. In addition there are 1 million Israeli-Arabs with full citizenship inside the Jewish state. Recent research found the Muslim birthrate exceeds Jewish births by 3-1 inside Israel.

In the pre-state period and the early years after independence, pioneers viewed the employment of Hebrew labor as an essential element of the Zionist mission. The farmers of the kibbutzim and the manual workers were valued as the Zionist elite, the new Jew building the land.

But after the 1967 Middle East War, Israel's standard of living began to improve rapidly. The Israeli economy expanded, partly fueled by the availability of cheap Palestinian labor from the recently occupied West Bank and Gaza Strip.

Now, the pioneering spirit is largely dead. Most Israelis, even those out of work, refuse to do low-paid, physically demanding jobs. Employers preferred to hire Palestinians because they would work longer hours for less pay. Today, the same is true for foreign workers.

In May alone, Israel "imported" 2,000 Thai workers to harvest the vital citrus crop, a job in sweltering heat previously carried out by Palestinian laborers. The Thais live in buildings and campers on farm property.

There are about 60,000 legal workers from the Philippines in Israel, 40,000 from Romania and 35,000 from Thailand. Others come from China, the former Soviet Union, Africa and South America. In Haifa, Turkish workers are bused every day to their jobs in the naval shipyard. A part of Haifa is known as "Little Turkey."

"We have to offer incentives to Israelis to do these jobs again - incentives like cut tax rates, free transport and good wages," said Yuri Stern, a deputy minister for labor in Prime Minister Ariel Sharon's coalition government. Religious and nationalist parties this summer had to shelve their proposals to crack down on illegal immigration after protests by industrialists, mainly building contractors. Their plants and construction sites were idle after Palestinians were barred from jobs in Israel.

Even if peace comes to the region, the future for Palestinian workers in Israel is not bright.

"We will never go back to the numbers and proportions of Palestinian labor as it was before the intifada," Stern said. "Employers would simply not take the risk to their own lives."