Although representatives of major business organizations yesterday expressed strong support for the Reagan administration's economic program, they also attacked the president's proposals to raise the taxes of their corporate constituents.

Responding to complaints from the president himself that business support is waning, Richard L. Lesher, president of the Chamber of Commerce, said his organization has "not backed off one bit."

But Lesher said in his prepared statement for the Senate Finance Committee that the administration's proposed corporate minimum tax has "no adequate rationale," will "undermine the accelerated-cost-recovery system," and will "cause great complexity in business planning." In short, he said that "any major tax increase now"--including those initiated by the administration--"would be economic suicide."

Similarly, Paul R. Huard, vice president of the National Association of Manufacturers, declared that "NAM strongly supports the president's program for economic recovery," but the administration's tax increases would take back the equivalent of "73 percent of . . . the corporate tax cuts" for 1983 and 1984.

"NAM opposes any major increase in business taxation," Huard declared.

In making their comments, the business groups appeared to be distinguishing between the president's proposals last year, all of which were beneficial to the business community, and his 1982 program, which includes new corporate taxes. The 1981 program generally was described as "the administration's program," while the 1982 tax proposals were treated as violations of the 1981 program.

Theodore F. Brophy, chairman of General Telephone & Electronics Corp. and cochairman of the Business Roundtable, an organization of the nation's largest corporations, told the panel that the Reagan "administration has set the proper long-range course for economic recovery."

However, Brophy contended that the proposed corporate minimum tax would "constrain corporate cash flow . . . fall unevenly throughout industries and taxpayers . . . neutralize many of the benefits" of the 1981 tax bill, reduce the "value of the investment tax credit . . . lead to future busines tax increases" and "add tremendous complexity to the tax laws."

These major business groups, along with Charls E. Walker of the American Council for Capital Formation, split on postponing the 1983 individual tax cut as a possible mechanism to reduce future deficits.

The Roundtable and Walker both suggested that, as a last resort, the 10 percent individual cuts for 1983 might be postponed, but both NAM and the chamber continued their firm support for maintaining the scheduled reduction.

"The American people need and deserve the full 25 percent reduction in tax rates that Congress promised them last year," Lesher told the committee. President Reagan has sponsored the corporate minimum tax, but he has remained opposed to postponement of delaying the individual rate cuts.

While indicating a willingness to support some modification, the chamber, NAM and Walker all opposed substantial restriction or repeal of the controversial leasing provisions of the 1981 tax bill that allow corporations to buy and sell tax breaks. The Roundtable, however, said that it would support "tightening of . . . leasing rules to eliminate any potential for abuse."

Although the corporate minimum tax is sparking the strongest adverse reaction from business opposition, NAM also declared its opposition to such administration initiatives as elimination of the tax deferral available to corporations performing long-term contracts.