Israeli Defense Minister Ariel Sharon last night defended his country's actions in Lebanon against criticism to an audience of about 600 Jewish delegates from across the United States here for a national conference of the Israel Bond Organization.

The defense minister, who got a standing ovation from the crowd, was most vehement in countering reports that his actions in Lebanon had not always had the advance approval of the Israeli cabinet.

"I want to tell you here, looking into your eyes, that every part, every phase, every step taken in Lebanon was taken entirely and completely in accordance with resolution and decision of the Israeli cabinet from the first day to the last day, including the heavy bombing of Beirut," Sharon said.

Sharon said he believed the civilian casualties in Lebanon numbered "around 2,000." Three-hundred-and-fifty Israeli soldiers were killed in the fighting, Sharon said, and his forces suffered 2,000 wounded.

The "victory" in Lebanon, Sharon said, was both a political and military defeat for the Palestine Liberation Organization and has "changed all the situation in the Middle East."

At the conference, the Jewish community leaders formally pledged to raise $550 million by the end of the year for Israel's economic development, thereby indirectly helping defray the cost of the war in Lebanon.

If the target is reached, it will be the largest annual sale of bonds by the Israel Bond Organization, according to its general chairman, Sam Rothberg of Peoria, Ill.

The organization is a worldwide body that seeks to raise development capital by selling Israeli securities. Its previous record for annual sales was set in 1973, the year of the Yom Kippur war, when the organization raised $515 million for Israel.

On Friday, Israel's ambassador to the United States, Moshe Arens, told the annual conference that the war is expected to cost Israel $3 billion to $4 billion -- one-quarter of the country's annual gross national product.

Rothberg said his organization began an emergency campaign to raise extra money for Israel the second week of June, shortly after the Israelis invaded Lebanon. The response has been good, Rothberg said, and the organization has raised $65 million more than it did in the same nine weeks of 1981.

Arens told the Jewish leaders that Israel's intervention in Lebanon had served U.S. interests in the Mideast by dealing "a blow to the solar plexus of the communist world of the Soviet Union that will take them years to recover from. In the Middle East the stock of the Soviet Union today is down to zero. And there is only one power of any consequence in that area of the world today, and it is the United States."

Outside the Washington Hilton, where the conference met, more than 600 people took part in three separate demonstrations on different corners of Connecticut Avenue and T Street NW. Police said one man was arrested for disorderly conduct and another was cited for a minor traffic violation during the more than three hours of protest that were marked mostly by shouting.

The majority of the protesters belonged to the Nov. 29 Coalition, whose organizers said represents nearly 100 groups, including Jews who are opposed to the Israel invasion of Lebanon and support self-determination for Palestinians