President Reagan yesterday extolled the virtues of his 1981 business tax cuts and told a group of corporate executives that the administration is "looking at other things of the same kind."

But White House spokesman Larry Speakes later said the president did not have any new initiatives in mind, and was instead referring to proposals made in his State of the Union message last month, including new trade incentives.

Speaking by satellite television broadcast to an Arizona business conference, Reagan said the "great changes" in business tax laws made in 1981, including a cut in the maximum capital gains tax rate from 28 to 20 percent, had resulted in "greater investment."

The capital gains tax cut also means "the government is getting more revenue as a result of the reduction of that tax rate," he added.

Reagan's off-the-cuff suggestion that "we are looking at other things of the same kind" sent aides checking to see if anything new was under consideration. They said later there was not.

However, Treasury Secretary Donald T. Regan recently endorsed a proposal, backed by Senate Finance Committee Chairman Robert J. Dole (R-Kan.), to reduce the capital gains holding period--the time necessary to qualify for the 20 percent rate--from one year to six months.

In his prepared remarks via satellite to a group of businessmen who became president of their firms before the age of 40, Reagan also seemed to modify his recent statements about the problems of the nation's declining "smokestack" industries.

Recently, he has said that because of "structural" problems in the economy, many jobs in industries such as steel and autos will never come back and that high technology is the wave of the future.

But Reagan, who was elected in 1980 on the promise to revive those aging sectors of the American economy, added a new twist yesterday, saying that "Our traditional, basic industries are not about to die away. America must never abandon them, they are fundamental to our economic base."

Also yesterday, Rep. Jack Kemp (R-N.Y.) and Rep. Jerry Lewis (R-Calif.) met with Reagan on the administration's upcoming attempt to persuade Congress to go along with increasing the lending power of the International Monetary Fund. Kemp suggested that unspecified conditions be attached to the IMF funds.