West European negotiators have won unprecedented, unilateral concessions from Moscow in shipping talks here - thanks, partly, to evident Soviet concern over Western reaction to events in Poland.
European diplomats point out that, even without the Polish crisis, the Soviets had good economic reason for their first such retreat in an increasingly bitter battle with Western shippers for world cargoes.
The Soviets, making enormous gains against Western competitors by charging much lower prices, ''knew they were pushing us too far,'' one diplomat said. The Europeans, for their part, made clear in the Jan. 11 to 15 talks their determination to take ''unilateral measures'' against Moscow if it did not show more restraint.
There has been no reference to the talks, much less comment on them, in the official Soviet press.
But diplomats said the Polish crisis was clearly one element in determining the Soviet approach in the talks, with government and business figures from West Germany, France, Britain, the Netherlands, and Belgium.
They said that a Soviet negotiator had said privately that one reason for Moscow's willingness to offer concessions was concern over ''talk'' in Western Europe about possible sanctions against Moscow over Poland.
Although the West Europeans have not matched US sanctions, most have undertaken to try not to undermine the American moves. The other 13 NATO states have also said they will consider economic and other steps against Moscow should Polish martial law continue unabated.
European diplomats here are assuming a further reason for the Soviet position at the recent talks was the US move, in protest over the Polish military crackdown, to suspend talks on a new shipping accord with Moscow.
Insofar as the step presages a generally tougher US stand toward the Soviets on international shipping, one European diplomat commented, ''The Soviets presumably want to be able to point to the recent talks as an example of responsible Soviet action in shipping.''
Over the last decade, the West has repeatedly accused the Soviets of precisely the opposite attitude. Their subsidized state merchant marine has cut sharply into the Western share of traffic on various international routes.
Soviet officials, for their part, have dismissed Western protests as camouflage for a crisis in Western shipping.
But in the recent talks, diplomats say, the Soviets undertook to:
* Act on the principle that third-country carriers should not endanger the economic viability of shipping concerns of the countries directly involved in commerce.
* Cut Soviet shipments of coffee on the Central America-West Europe route by 30 percent.
* Limit the Soviet share of cotton shipments on that route to 20 percent of the market total.
* Cut pickups in West European ports of goods destined for East Africa by 10 percent.
These undertakings are to run for the current year. The percentages could be adjusted by mutual consent to allow for the possibility of a shrinkage in total shipping volume as a result of expected Soviet price increases. (The West Europeans did not seek a commitment from Moscow to match Western shipping prices. ''Both sides know that the quality of Soviet service is not equal, and accept this,'' said one diplomat.)
Diplomats said discussion of a further area of disagreement with the Soviets - the Far East - was complicated because European must compete not so much from Soviet ships, as with the trans-Siberian railroad.
But Moscow agreed to early talks on the issue, the diplomats said.
They reported that the Soviets also agreed to handle various shipping issues in the future in consultation with existing shipping ''conferences'' in affected regions