The AFL-CIO executive council unanimously approved a resolution today calling for a new income tax to finance future defense spending increases, including a proposed $33 billion increase in fiscal 1983.

The executive council said the new tax should apply to corporate and individual incomes on a weighted basis and would be an alternative to President Reagan's approach to defense financing, which the council said puts the burden "squarely on the backs of working Americans and the poor."

AFL-CIO President Lane Kirkland, emerging after a 2 1/2-hour meeting with the 35-member council at its annual midwinter meeting here, accused Reagan of an unacceptable trade-off in sacrificing social programs in a time of recession to increase defense spending.

"The Republican administration, through its economic policies, has deliberately set the stage for a revival of the destructive 'guns versus butter' debate; and it has made its choice clear--guns, not butter," the council said in a statement.

The resolution came one day before Vice President Bush is to meet with federation leaders to discuss the administration's economic policies and other matters. Secretary of State Alexander M. Haig Jr. is expected to take up foreign policy issues when he meets with AFL-CIO officials here Friday.

The council, which sets policy for the 15 million-member federation, traditionally has gone along with moves to increase defense spending. But it may abandon that posture now because it said this administration has no firm foreign policy and is increasing defense spending at the expense of the poor.

"The AFL-CIO's longstanding support for a strong national defense does not oblige us to support a defense budget that is unfairly financed," the council said. "Nor does our opposition to such financing compel us to join those who see little need for improving U.S. military capability and, therefore, urge deep cuts in defense spending to finance social programs."

The council voted to establish a seven-member committee to study the question. Kirkland said the panel will spend the next year meeting with defense experts on both sides of the spending issue and thus will not finish its work in time to offer recommendations on federation action regarding the administration's proposal to increase defense outlays $33 billion next fiscal year.

The administration has done much to unify the normally divided AFL-CIO leadership on the defense issue, according to one of the federation's leading hawks, Albert Shanker, president of the American Federation of Teachers.

"I am a super-hawk," Shanker said, "but the most important element in national defense is national will, and Reagan simply has not demonstrated that will"--either in his approach to foreign policy or his proposals for defense spending.

He accused the administration of waffling on the U.S. response to Soviet intervention in Poland and of wasting money on the MX missile and other weapons systems.

On the matter of spending, Shanker said: "If the country's future is at stake in terms of defense, then everybody ought to pay for it. Part of the whole question of national will has to do with who is willing to pay and how much."