Senate Foreign Relations Committee Chairman Charles H. Percy (R-Ill.) has joined allied leaders in urging President Reagan to submit a new proposal to break the deadlock with the Soviet Union in the intermediate-range nuclear arms talks in Europe.

Percy is the first high-ranking Republican to call publicly for a shift in the administration's stance in the Geneva talks, and his statement adds to the pressure already on the White House from western Europe to take some new action.

In a speech prepared for delivery today to an Air Force Association symposium in Rosement, Ill., Percy called for the administration to submit a new proposal "during the current negotiating round" of the talks, which are scheduled to adjourn late this month. "And if need be," he added, Reagan should "keep the two delegations in Geneva until we receive a Soviet response."

Percy argued that since Reagan has indicated he is prepared to be flexible at Geneva--he suggested in a speech last month that he might bend if certain principles were met--"there is no point in letting the Soviets score a propaganda coup by being the first to move away from their current negotiating position."

Earlier this week Italian Foreign Minister Emilio Colombo, in a visit here that included a meeting with Reagan, told reporters he also thinks the administration should put a new proposal on the table at Geneva.

Colombo said other allied officials share his view, and U.S. officials acknowledge that similar views similar are held by West Germany's newly elected conservative Chancellor Helmut Kohl and British Prime Minister Margaret Thatcher, among others.

At issue is whether Reagan is prepared to offer some compromise at Geneva as an interim step toward his original zero-zero proposal of November, 1981.

That zero-zero plan calls for the Soviets to dismantle all 600 intermediate-range missiles while the West gives up deployment of 572 new Pershing II and cruise missiles scheduled to begin in December in West Germany, Italy and Britain.

The allies have backed zero-zero as an ultimate goal. But the planned missile deployments are controversial, and the allies have made clear that they would like Reagan to offer some intermediate step to help ease their political burdens and demonstrate U.S. good faith.

Percy and Colombo argued that the German election results strengthen the hand of the administration, making it easier to show flexibility that will not be viewed as a sign of weakness. They also argue that if the Soviets show no interest in a new proposal, then it will be clearer to allied populations that it is Moscow that is responsible for lack of progress.

"Time is growing short in these negotiations," Percy said, and "I believe the time to move is now." Officials say privately that there is some consideration of a new move but no decision has been made.

Some sources believe prospects are increasing that some new move will be forthcoming, although the timing is uncertain.

Opponents believe the United States should stick to its original plan as long as necessary to convince the Soviets they have to be more forthcoming. The Soviets have made clear that they do not want any new U.S. missiles installed, and seem especially concerned about the Pershings, which can strike with virtually no warning time.