The threat of Warsaw Pact forces launching a sudden attack across the NATO front has been "overstated" and could lead to a dangerous over reaction in the West, Rep. Les. Aspio (D-Wis.) said yesterday.

Aspin, a member of the House Armed Services Committee and a former Pentagon analyst, urged Congress to reject recent advice to spend billions of dollars to make NATO forces better prepared to fight.

Such a buildup, Aspin argued might impel Soviet planners to do likewise along the NATO front and thus put a "hair trigger" on the situation.

The Soviets currently have so many obstacles to launching a "no-notice, bolt-out-of-the blue, sudden attack" that it is "pretty unlikely" that such a thrust could be launched successfully, Aspin said.

In saying that, he took issue with recent warnings by retired Army Lt. Gen. James Hollingsworth and Sens. Sam Nunn (D-Ga.) and Dewey F. Bartlett (R-Okla.), who said in recent reports that Warsaw Pact forces have been improved to the point that they pose the danger of attacking with less warning thatn NATO strategists are counting on in their war plans.

Aspin, in a contrary view, said Czech, East German and Polish divisions - which constitute 27 of the 54 divisions in the Warsaw Pact available for a thrust against NATO - are undermanned and underequipped. The remaining 27 divisions available for a thrust against are Soviet.

If the Soviets relied solely on their own divisions, Aspin said, they would be counting on troops stationed farther from the German front than their opponents on the NATO side of the line. Soviet forces have not overcome the supply problems that "left their unopposed armored and mechanized divisions without many basic supplies on the third day of the 1968 invasion of Czechoslovakia," Aspin asserted.

He added that "it is hard to believe" that the Soviets would launch a land attack against NATO without also sending their navy to war. "Soviet naval activity would provide early warning of an impending conflict," he argued.

Rather than invest billions of dollars to prepare NATO forces to go to war within 48 hours, Aspin recommended focusing NATO Warsaw Pact negotiations on reducing the risk of surprise attack. He complained that those negotiations have concentrated too heavily on reducing the number of troops on each side rather than exploring other diplomatic options.

He said negotiators should work toward putting international observers at NATO and Warsaw pact installations, limiting the size and frequencies of military maneuvers that might disguise mobilization for an attack, and requiring advance notice whenever new troops are rotated into an area on either side of the German front.