JERUSALEM, SEPT. 16 -- Israel, under strong pressure from American blacks and Jews, today imposed 10 economic and cultural sanctions against South Africa. All are largely symbolic but they represent another step in Israel's gradual move away from the close relations it has long had with the Pretoria government.

Officials here said the measures, which include bans on new investments and on governmental, scientific, sports and cultural exchanges between the two states, were designed to bring Israel into line with western restrictions on South Africa and to placate American public opinion. They are modeled after the measures adopted by the European Community rather than the tougher sanctions enacted by the U.S. Congress last year and sustained over a presidential veto.

The sanctions, first proposed by a special committee in June, had been shelved by Israel's policy-making inner Cabinet in July. But they were hurriedly revived after a delegation of black American businessmen, politicians and clergy warned officials earlier this week that Americans were still concerned about Israeli-South African ties and that the issue could cause Israel problems with Congress.

One indication of the sensitivity of the issue here is that a planned news conference featuring Yosef Beilin, political director general of the Foreign Ministry and principal architect of the sanctions, was changed at the last minute at the request of Prime Minister Yitzhak Shamir. Beilin did not appear, and reporters were simply told that the measures had been adopted by the inner Cabinet but were not told what they were.

One of Shamir's top aides, Cabinet Secretary Eliakym Rubinstein, later said the details would not be announced for several days to give Israel time to communicate them fully to South Africa and to governmental ministries here. Meanwhile, however, they were leaked.

Nonetheless, their adoption was a political triumph for Beilin, who is a top adviser to Foreign Minister Shimon Peres and is expected to run for the Israeli parliament next year. He had been pressing for months for the measures against strong opposition from some influential leaders of his own political party, the more dovish Labor Alignment.

Those opponents have included Defense Minister Yitzhak Rabin, a Laborite, as well as former defense ministers Ezer Weizman, Moshe Arens and Ariel Sharon, all of whom are members of the inner Cabinet. They had argued that Israel's beleaguered economy needed all the trading partners that it could get and that South Africa had been a steadfast ally and partner in the 1970s when the rest of Africa cut off ties with Jerusalem.

Despite the 1977 U.N. arms embargo against Pretoria, which Israel claimed to observe, secret military contracts between the two nations range from $125 million to $400 million a year, according to various published estimates. Israel has also claimed a special stake in South Africa because of the presence there of 110,000 South African Jews and 15,000 Israelis.

But last March, Beilin and Peres -- with strong support from American Jewish lobbying organizations -- persuaded the inner Cabinet to endorse a change in Israeli policy, denouncing the apartheid system of white political domination and pledging to let Israel's extensive network of defense contracts lapse over an unspecified period. The move, taken in response to American pressure after Israeli embarrassment over the Jonathan Pollard spy affair, was made public 10 days before a State Department report outlining some of Israel's links with South Africa.

The Cabinet also set up a five-member panel, chaired by Beilin and including representatives of the ministries headed by Shamir, Rabin, Sharon and Finance Minister Moshe Nissim, to come up with other measures.

It produced a list of 13, but by the time the inner Cabinet took them up in July, international pressure had eased and the Cabinet, pushed by Rabin and Weizman, decided to put off action indefinitely.

Then this week, a group of 22 black American leaders, sponsored by the Anti-Defamation League of B'nai B'rith and led by the Rev. Charles Stith of Boston and Martin Luther King III, met with Peres and Beilin and pressed for further action.

"I believe the concern of American public opinion as conveyed by the delegation helped lead to this decision," said Harry Wall, the ADL's Israel representative. "It should have great resonance among Americans, black and Jewish, who are opposed to apartheid and who were concerned about Israel's reputation."

Among the measures adopted today are a ban on receiving loans from South Africa, a freeze on the amount of steel imports and a commitment that Israel will not allow itself to be used as a transshipment point for South African goods and purchases.

If fully enforced, the last measure could be of particular importance because Israeli businessmen have been widely reported to be offering to help Pretoria circumvent sanctions by serving as middlemen to disguise the origin of South African exports and the destination for its imports.

Some of the sanctions, including bans on the purchase of krugerrand gold coins and on oil sales, are entirely symbolic. Local import restrictions already made krugerrand purchases next to impossible, and Israel does not trade in petroleum products with South Africa.

Another measure calls for establishment of a fund to finance travel to Israel and training sessions here for black South African community leaders.

Other Beilin proposals did not get through the five-member panel. Those included a requirement that South Africans obtain visas to enter Israel and a ban on equipment such as certain computers that have potential military as well as civilian applications. Such restrictions have been imposed by most other western nations.