Defense Secretary Caspar W. Weinberger said yesterday that hostilities in the Persian Gulf would need to grow "a great deal more than what is occurring now" to meet the requirements for invoking the War Powers Resolution that would give Congress authority over U.S. military activities in the region.

Weinberger, who is scheduled to return to Washington today after a five-day trip to the Middle East, attacked as the "height of absurdity" proposed legislation that would require congressional approval to continue the administration's controversial program of escorting through the gulf Kuwaiti tankers that now fly the U.S. flag.

Senate Democratic leaders, trying to avert a showdown on the War Powers Resolution, have proposed an amendment to the defense authorization bill that would impose many requirements of the 1973 resolution without formally invoking the law.

"What we're talking about now is an amendment . . . that would provide that we must keep a strong presence in the gulf, but we can't do anything," Weinberger said from Bahrain in an interview on ABC's "This Week With David Brinkley."

"We have to unflag the ships that have been flagged according to proper American legal procedures, and we're not allowed to convoy. So what in the world would we do? It is, I think, the height of absurdity."

President Reagan, charging that the congressional proposal could have "disastrous effects" on U.S. commitments in the gulf region, has said he would veto any plan requiring congressional approval for continuing the escort operation for more than 90 days after enactment of the legislation.

"What we're doing is very important," Weinberger said of the decision to provide military escorts to the 11 reflagged tankers. "There's a very real menace, it's not just a threat of Soviet domination of the Persian Gulf."

But Sen. John Glenn (D-Ohio), a member of the Armed Services Committee who also appeared on the program, countered that the situation in the gulf borders on war.

"If there ever was a situation that called for reporting {under the War Powers Resolution}, this is it," Glenn said.

Weinberger said he believes that U.N. imposition of an arms embargo that "would be genuinely enforced" could help bring about an end to the seven-year war between Iran and Iraq.

"Short of that, we will need a totally different kind of government in Iran," he said. "No one can deal with the irrational, fanatical government they have now."

Weinberger refused to discuss details of his meetings with government leaders in Saudi Arabia and Bahrain during his visit.

"We have enormous cooperation here," he said. "The less we talk about it, the more we get."

Some military officials have criticized the gulf states for not providing the United States with enough bases or other military support.