Senate Armed Services Committee Chairman Sam Nunn (D-Ga.) said yesterday that President Reagan's plan to protect Kuwaiti oil tankers in the Persian Gulf is a "strong tilt towards Iraq" in its war with Iran, and he advised the administration to delay implementation.

Nunn said the United States would be making a "fundamental error" in placing the Kuwaiti ships under the U.S. flag unless that were made part of an overall U.S. policy in the gulf. "This Kuwaiti flagging is a symbol of an absence of policy, and we've got to force the administration to have an overall policy before we decide this issue," Nunn said.

Former secretary of state Henry A. Kissinger, who appeared on NBC News' "Meet the Press" with Nunn, also said the move would be a mistake.

"By our getting involved, in effect, on the Iraq side, we are taking on a belligerent commitment in a war in which it isn't clear to me how it is going to end," Kissinger said.

The Nunn and Kissinger statements represent a widening uneasiness with Reagan's policy in the gulf. The possibility that Iran may deploy ship-attacking Chinese Silkworm missiles above the Strait of Hormuz at the narrowest point in the gulf makes critics more anxious. The missiles make U.S. ships more vulnerable.

An Exocet missile attack on the USS Stark by an Iraqi jet killed 37 sailors last month. Both Iraq and the administration said the attack was an error.

Nunn said yesterday that the decision to protect Kuwaiti ships constitutes a tilt toward Iraq in the 6 1/2-year war. Although the administration has said that the goal is to protect the free flow of oil, it has not proposed to defend oil tankers of other nations, Nunn said. More oil leaves the gulf in Iranian ships than in Kuwaiti tankers, and the Iranian vessels will be vulnerable to Iraqi attack.

"We have basically taken a strong tilt towards Iraq," he said. "That ought to be debated on its own merits, and not under the illusions that we're really protecting the free flow of oil."

Although he has criticized the reflagging plan before, Nunn had never called for delaying its implementation. Under the plan, 11 Kuwaiti tankers would fly the U.S. flag and ply the gulf under protection of U.S. forces. The Soviet Union is taking similar action with three Kuwaiti tankers.

Kissinger said that he favors maintaining free navigation in the gulf and that he would back the administration if gulf passage were threatened. "I'm not persuaded that we are now facing a threat to freedom of navigation," he said. "From what I now know . . . I think it's a bad idea to get ourselves militarily involved."

Nunn and Kissinger disagreed on whether there might be circumstances under which the United States and the Soviet Union should cooperate in the region. "The central issue is how do we end the ground war," Nunn said. "That's where the United States and the Soviet Union may have a convergence of interests."

But Kissinger said he has a much more limited view of desirable cooperation. "Of all the areas in the world in which I don't think our interests are parallel, the Persian Gulf is one of the most preeminent," he said. "We may have a very short-term common interest, but I would not consider that an area for superpower cooperation."

In determining U.S. policy in the region, Nunn said that Congress should not be the "lead partner," but should play a "crucial" role. "We're asking the hard questions, and they haven't thought through the questions," he said. "They haven't thought through the answers . . . . So we do have to put our show together, so to speak, and it has to be developed jointly with the administration and with Congress."

In other remarks, Nunn criticized Elliott Abrams, the assistant secretary of state who has admitted to and apologized for misleading Congress in the Iran-contra affair. Although Nunn seemed to give Abrams a vote of no confidence, he stopped short of calling for his resignation. "He is a very capable individual, but his credibility has been severely damaged and when we debate the overall aid to contras in the fall of this year, his presence will not be helpful," he said.