The Reagan administration is objecting to the strings the Soviets attached to their offer to dismantle the disputed Krasnoyarsk radar complex in Siberia.

State Department spokeswoman Phyllis Oakley on Wednesday said the Soviet Union should meet its obligations under the 1972 Anti-Ballistic Missile treaty by agreeing to scrap the facility "without delay and without conditions."On Tuesday, Viktor P. Karpov, the Soviet foreign ministry's top arms control specialist, said the Soviets would dismantle the radar complex if the two governments resolved their differences over the ABM accord.

"If an understanding to abide by the ABM treaty, as signed in 1972, is reached, the Soviet Union will be ready to dismantle the Krasnoyarsk radar in a verifiable way that would leave no doubts on the part of the United States," Karpov said.

In Santa Barbara, Calif., White House spokesman Marlin Fitzwater said the Krasnoyarsk facility should be dismantled without any strings attached.

"The fact is that we have long said the Krasnoyarsk radar is a violation of the ABM treaty and should be dismantled," he said. "We welcome their remarks in the sense that they do acknowledge that it is a violation of the ABM treaty. . . . And in that acknowledgment we believe ought to be recognition that it should be torn down, but no strings and no deals."

Karpov's offer seemed to be a Soviet concession, since the Soviets previously had insisted on disrupting U.S. plans to upgrade radars in Britain and Greenland that Moscow had questioned.

Oakley said Krasnoyarsk would be one of the central topics of the review of the treaty the two sides are obliged to hold by October. "We are concerned about a variety of Soviet ABM-related activities that suggest the USSR may be preparing a territorial defense," Oakley said.

The treaty constrains U.S. and Soviet anti-missile defenses on the theory the prospect of devastating retaliation might deter a potential aggressor.