VIENNA, Austria (AP) _ The Warsaw Pact proposed Thursday at the troop reduction talks that nations be able to reject inspections, but NATO rejected that as a throwback to positions that have stalemated the negotiations.

Until Thursday, there had been cautious talk by both sides that the negotiations, deadlocked for more than 12 years, had begun to show progress, but Western negotiators said they were disappointed with the latest proposal.

''It was like listening to a record you've heard many times before,'' said a senior Western negotiator, who spoke on condition of anonymity.

The talks are intended to reduce the estimated 2 million troops, stationed by NATO in the Netherlands, Belgium, Luxembourg and West Germany and by thte Warsaw Pact nations in East Germany, Poland and Czechoslovkia.

The main snag is over how to police an eventual agreement to make sure there is no cheating.

East German Ambassador Andre Wieland, who submitted the Warsaw Pact proposal, told reporters the communist side wanted a system allowing each side the right to refuse a request to conduct troop inspections.

''Such an approach ... would provide a built-in right to veto legitimate inspection requests,'' said Netherlands Ambassador Jan Hein van de Mortel.

After some earnest bargaining over the past few months, the two sides are close to agreement on how many troops should be pulled out in a first-phase withdrawal. The East wants 11,500 Soviet soldiers and 6,500 Americans withdrawn; the West proposes 11,500 Soviets and 5,000 Americans.

There would be no increases for three years after the withdrawals, which would only involve Soviet and U.S. troops in the initial phase.

To guarantee that, the Warsaw Pact envisions setting up three or four checkpoints on each side to watch movements, but the West also wants each side to have the right to conduct 30 inspections a year.

''As a rule, such requests shall be granted,'' said the East German ambassador. ''A refusal must be accompanied by a sufficiently convincing explanation.''

''Of course the system falls apart if the other side can say 'No,''' said the Western negotiator.

The West claims it revived the talks by agreeing last December to drop the ''data issue,'' the previous sticking point. NATO claims its forces are outnumbered by about 200,000 Warsaw Pact troops.

The East says numbers are about even at 990,000, but last December NATO shelved the issue and proposed beginning withdrawals.

''The East has fallen back once more upon its inadequate proposals of former years and has failed to move substantially on any significant issue dividing the side,'' said van de Mortel.

Soviet leader Mikhail S. Gorbachev has said the Warsaw Pact was seeking an end to the stalemate and was serious about an agreement.

The senior Western negotiator suggested the Kremlin leadership may be concentrating on the Soviet party congress due to begin Feb. 25 and was not behind the latest proposal. He speculated there could be another after the congress.

''Their response was so unoriginal ... a lieutenant colonel could have approved what they said today,'' he said. ''We on the Western side are just going to have to wait and see.''