The worsening crisis in Iran and the prospect of a radical leadership succeeding Shah Mohammad Reza Pahlavi is causing growing anxiety in Israel, which long has been comforted by its Iranian link to the Moslem world as well as being warmed by Irans once-bountiful suply of oil.

The instability in Iran, Israeli government officials say, potentially overshadows in imprtance the current Middle East peace negotiations because of the geopolitical implications of a steadily growing Soviet influence in the Persian Gulf region.

Sandwiched between Iraq and Afghanistan, Iran is viewed by many Israelis as the last solid bulwark of political moderation in the area. The shah's collapse, it is feared here, would inevitably lead to similar instability in Saudia Arasbia and other Gulf states.

Moreover, Israeli officials say, they are concerned that the revival of Islamic fundamentalism is not just an Iranian phenomenom but is one that is spreading throughout the Moslem world as evidenced by recent disturbances in Turkey.

"I've never been the shah's greatest admirer, but what is happening in Iran today cannot be regarded as a localized, internal problem. It will effect the whole area and, eventually, will have security implications for the whole free world," said one official.

What some Israelis fear most -- and see as an immenent possibility -- is that the shah may cast aside his tentative ties to Israel in a last-ditch effort to apease the opposition and that Israel would be left in the cold even if the shah managed to retain his throne.

For practical reasons, however, Israel's leaders have tried to keep anxiety hidden, and their public statements cautious andrestrained.

For one thing, there are approximately 60,000 Jews living in Iran, the vast majority of them Iranian nationals, and they have been subjected to increasing attacks by Moslem extremists, not necessrily on the basis of anti-Semitism but as an outgrowth of the widespread suspicion of all foreigners.

"We feel we shouldn't put the Jewish people there in danger any more than they already are," a Foreign Ministry official said.

Jews have been living in Iran for 2,000 years, since Cyrus the Great freed Jewish slaves in Babylon and brought them to Iran. Now, thousands of Jews have left Iran. Now, thousands of Jews have left Iran on tourist visas, presumably intending to return to protect their investments, but relatively few have chosen to go to Israel.

Ayatolla Ruhollah Khomeini, exiled leader of the dominent Shiite Moslem sect, has repeatedly issued inflamotory statements about Iranian Jews, and other Moslem leaders in Iran have warmed about "bloodsucking Jews" having to leave Iran by February.

Another element is that Israel and Iran all along have maintained what one Foreign Ministry official today described as a "semi-nonexistant relationship." Traditionally, officals of both countries have tried to avoid discussing the tentative bond -- the shah to avoid the wrath of other Moslem nations, and Israel for fear of upsetting the delicate trade arrangement that plays a significant role in the economy here.

The two countries do not have diplomatic ties, but each maintains a trade mission in the other's capital. El Al, the Israeli airline, operates daily service between Tehran and Tel Aviv, and Israel now is exporting $120 million worth of goods a year to Iran.

Israeli exports to Iran were stopped as of today, however, because port strikes in Iran have made it impossible to unload freighters. A ship due to leave Eilat was called back because another Israeli ship is stuck in Iran unable to unload its cargo.

Of more immediate concern to Israel has been the abrupt cutoff of Iranian oil, which Israeli Energy Minister Yitzhak Modai last week called "Israel's second greatest survival problem after the question of security."

While that characterization struck some officials as immoderate, particularly in light of Israel's success in finding alternative sources of crude oil, the virtual standstill in Iran's oil production has created a potentially serious energy problem for Israel.

Iran has been supplying Israel with slightly more than half of the 54.6 million barrels of oil Israel consumes annually, and during the last several days the imports have dried up completely.

Officials note, however, that Israel's consumption is a miniscule fraction of the oil sold on the world market and that alternative sources had been found before the situation in Iran worsened in the last two months.

Israel has turned to Mexico, which previously had supplied about 10 percent of the country's needs, and shipments already have been increased. Modai this week said that Israel already is better off than most European countries and the United States because of its oil reserves and alternative sources.

"I can say with confidence that the supply of oil to the state of Israel is already assured to a satisfactory extent both under present conditions and in case of an emergency," Modai said.

The emergency contingencies presumably referred to a three-year-old agreement with the United States in which the U.S. government promised to fill all Israel's oil needs in the event of a regional crisis. In the event of a worldwide shortage, the United States agreed to fill Israel's essential oil needs.

The commitment was made in 1975 as part of the Sinai interim withdrawal as an inducement to get Israel to cede the Abu Rodeis oil fields to Egypt.

Prime Minister Menachem Begin, speaking to Israeli newspaper editors at a luncheon today, said that "the commitment stands, as I heard from a U.S. source personally."

Israel also has its Alma oil fields in the Suez Gulf region, which produce 29,000 barrels of crude daily, or about 15 percent of the countryhs consumption. By the end of 1979, Israel expects the Alma fields to be producing a third of the country's need.

Israel also reportedly has an oil sale reserve here that is equivalent to 100 million tons of fuel.