The meeting of the International Telecommunications Union, which attracted widespread attention when Arab countries tried to expel Israel, ended yesterday with approval of budget increases opposed by both the United States and the Soviet Union.

The approval of an effective 6.45 percent budget increase for next year and technical assistance for poor member countries was seen as a modest victory by Third World nations. This year's budget was $47 million.

The head of the U.S. delegation, Washington attorney Michael R. Gardner, said at the end of the meeting: "We are not going home to trumpets, but we have been reasonably successful even though there has been a definite shift in the focus of the ITU."

The polarization between the industrialized countries of the Northern Hemisphere and the poor nations of the Southern Hemisphere infused the six-week meeting with distracting political undercurrents. The most imflammatory was the effort to expel Israel from the 157-member U.N. agency that governs international cooperation in telecommunications. The attempt to strip Israel of its credentials because of the invasion of Lebanon was quashed only after the United States threatened to suspend its annual $3.2 million contribution to the ITU.

The United States, Britain and the Soviet Union all expressed formal reservations on the contents of the new budget, which will reduce staff and administrative expenditures but be weighed more heavily toward technical assistance. Addressing ITU delegates Thursday, Gardner expressed concern over the agency's "regrettable and pervasive lack of realistic fiscal planning, the politicization of the union and a requirement that the union provide technical cooperation and assistance."

In private, U.S. conference officials have expressed even stronger reservations on the outcome of the vote, which is in direct conflict with the stated U.S. congressional intent of barring technical assistance from the budgets of specialized U.N. agencies. They have implied that the budget as it stands will encounter serious difficulties in obtaining congressional ratification.

"We are really playing hardball with U.N. budgets throughout the U.N. system. We feel that at a time when domestic budgets are being cut back international organizations ought to be doing the same thing," a U.S. official said.

Although U.S. diplomacy has stumbled occasionally at the ITU meeting, good will was generated among Third World members with the offer of private sector technical training under the umbrella of the U.S. Telecommunications Training Institute. The nonprofit organization, established last month, is a brainchild of Gardner.

"If we had come here with a no-no attitude, the conference could have been much more polarized," he said. "There were some predictable trends, but I think we minimized the adverse effects."

The free training for Third World technocrats and bureaucrats is meant as a way for them to get a foothold in the $300 billion international communications market, now dominated by Japan and West Germany.

Next year the institute plans to give about 300 students from developing nations two- to six-week courses at such communications giants as AT&T, MCI, IBM, Rockwell International and RCA. The companies are bearing the costs for the courses.

ITU meetings have important technical, economic and military implications for the United States and other Western countries as they establish guidelines for allocating radio frequencies and slots in space for communications satellites. The West seeks to safeguard its dominant position, while the developing countries exercise political muscle in a bid to reserve future space for their own telecommunications networks that are yet to be developed.