A week before his summit meeting with Soviet leader Mikhail Gorbachev, President Reagan has decided to charge the Soviet Union with a new violation of the 1972 Antiballistic Missile (ABM) Treaty, senior U.S. officials said yesterday.

The alleged violation, expected to be reported to Congress today in the administration's annual Soviet arms control compliance report, involves several old radars the Soviets moved to new locations this year, although the ABM treaty requires that they remain at a designated ABM "test range."

Reagan made his decision Monday after hearing from senior arms control and military advisers, some of whom argued that the Soviet action was ambiguous, had little military significance and needed further investigation before any conclusions could be reached, the officials said.

These advisers, including senior State Department representatives, pointed out that the Soviets invited the United States in October to conduct an on-site inspection of one of the radars and argued that it was premature to charge the Soviets with a treaty violation while the offer is pending.

The administration responded to the Soviet offer last month by asking to inspect the radars, located in the Moscow region and at an electronics plant in the city of Gomel, north of Kiev. The administration is still awaiting a Soviet response to this counteroffer.

The officials said the "violation" claim was initially pressed by the Defense Department and vigorously opposed by the State Department. The Arms Control and Disarmament Agency (ACDA) took the intermediate position that the radar redeployments were a "probable violation" but that further investigation was needed before making a firmer allegation.

Some officials also argued that release of the annual compliance report should be delayed until after the summit's conclusion. But conservatives on Capitol Hill, unhappy with the summit and the intermediate-range nuclear forces (INF) treaty to be signed there, pressed the White House not to delay the report past Congress' Dec. 1 due date.

The Defense Department position on the radars was set by Caspar W. Weinberger before he left office as secretary of defense on Nov. 20. It could not be learned last night what role Weinberger's successor, Frank C. Carlucci, played in the administration deliberations although several officials said they saw no shift among lower-ranking Pentagon officials after Carlucci took office Nov. 23.

The radars, called Flat Twin and Pawn Shop by analysts, were built in the early 1970s at Saryshagan, a missile test range in the south-central Soviet Union, and were moved to Gomel and the Moscow region this year.

U.S. intelligence officials said the radars were designed to track incoming U.S. ballistic missiles and guide Soviet antiballistic missiles to destroy them with nuclear explosions. U.S. officials said this makes the radars subject to an ABM treaty requirement that such radars be deployed only at agreed test ranges.

The treaty provision aims to bar the superpowers from using such radars to help create a nationwide ballistic missile defense. Reagan decided to repeat in the new compliance report a previous charge that the Soviets "may be preparing" such a defense. Officials said he rejected a Defense Department plea that the report declare the Soviet Union "is preparing" a national ABM defense.

None of the radars at issue is close enough to Soviet missile silos to figure in such a missile defense, nor have any missile interceptors been detected nearby, U.S. officials agreed. There also is broad agreement that the radars are outmoded and that hundreds of more modern versions would be needed in a credible ABM system.

The Soviets said electronic equipment for Pawn Shop was not reinstalled after the move, and invited U.S. inspectors to verify the claim. The Soviets also said the Flat Twin radar was not fully reassembled.