The fifth year of East-West talks on reducing military forces in central Europe ended here today without progress or even a procedural breakthrough that could open the way for significant negotiations.

The head of the Soviet delegation, Nikolai Tarasov, warned at the final session of this round of talks that any attempt by the North Atlantic Treaty Organization to deploy cruise missiles or neutron bombs on the central front in Europe as "a trump card in Vienna" would "create insurmountable obstacles in these negotiations."

Warsaw Pact speakers criticized last week's meetings of NATO defense and foreign ministers in Brussels where various governments promised to take steps to improve the equipment and readiness of NATO forces. Foreign ministers also decided to try to inject some momentum into the force reduction talks. Nevertheless, Western delegates maintain that the Warsaw Pact side is a long way from negotiating yet.

The talks have been stalled on the question of exchanging troop data, comparing them with intelligence estimates and then reconciling differences. Agreement on what procedure to follow has eluded the delegates here for five years.

The Warsaw Pact did submit a total for its land and air forces on the central front about 15 months ago of 987,000 men not including forces in Hungary.

Dutch Ambassador Wilhelm de Vos, addressing a press conference today, said that this figure is 150,000 below NATO estimates "at a minimum, probably more." A Soviet journalist asked why the NATO Powers distrusted its partners in the negotiation.

De Vos replied: "It is not that we distrust. We believe our figures are more accurate, and we want to know the reasons for the discrepancy. Maybe there are hidden explanations we are not aware of. A good discussion on data that will clarify these discrepancies would establish confidence on both sides in what we are going."

The figure for the equivalent NATO forces is 921,000, not including the French. For the last year, the main effort here has been to get the Soviet delegates to break down their 987,000 figure into three categories: fighting units, support rear echelon troops and headquarters units. In late October, the Soviet delegates partially accepted this idea. But now the agreement has been derailed again.

The Warsaw Pact has come back with a "procedural point" that, in effect, prohibits any challenge to the data breakdown once it is on the table. Since NATO still wants to establish the whereabouts of those "missing" 150,000 men - the equivalent of 10 divisions - the western delegates are insisting on the right to challenge the other side's data.

Negotiations are to resume Feb. 1.