Cracks appear in Europe's unconditional support for Britain in Falklands

Slight cracks have begun to appear in the once-flawless wall of West European support for Britain in the Falklands crisis.

Few observers have suggested that the wall will collapse tomorrow, forcing Britain to reconsider its commitment to winning back the islands. But some NATO watchers have started to worry.

Initially, support for Britain was quick and tough.

Argentina invaded the islands April 2, and within days the 10 European Community (EC) countries had slapped an arms embargo on Argentina and banned Argentine imports worth almost $2 billion a year. Such action was unprecedented in EC history.

Officially the EC and almost every other country in Western Europe remain as steadfast--at least diplomatically--behind their British ally today as they were five weeks ago.

(An exception is Ireland, which denounced Britain as the aggressor May 4 and said it would seek an immediate UN Security Council meeting to propose a resolution to end the fighting, Reuters reported.)

On May 3, EC President Leo Tindemans, the Belgian foreign minister, restated the EC's ''solidarity'' with Britain. And in Strasbourg last week, foreign ministers from 21 countries of Europe repeated an earlier demand for an immediate withdrawal of Argentine forces from the Falkland Islands.

Beneath the official rhetoric, however, lie serious misgivings among some senior government planners and the public alike over the direction of British policy--especially with the May 1 and May 4 bombings of the airstrips on East Falkland Island, and the sinking of two Argentine ships May 2.

Those concerns, according to diplomatic sources, were reflected at a meeting of top EC foreign ministry officials in Brussels May 4. Several countries, including West Germany, Italy, Denmark, and Ireland, said that they may not be prepared to extend the imports ban against Argentina beyond May 17, the agreed expiration date.

Privately, government officials in West Germany (Argentina's most important trading partner in Western Europe) have expressed concern over Britain's willingness to use military force before all diplomatic efforts to resolve the conflict had been exhausted.

Chancellor Helmut Schmidt was reported in the news magazine Der Spiegel to have told his Cabinet last week that West Germany had not given Britain a blank check. The magazine said that Mr. Schmidt privately regards Britain's Falklands operation as anachronistic and a danger to international relations.

In France, which has islands of its own to consider, official support for Britain remains unflinching, although the Paris daily Le Monde May 4 showed some unrest by saying that the British military operations would ''unleash a formidable anti-European wave in most Latin American countries.'' The newspaper called the conflict a gift to the Soviet Union.

But in Italy--where a willingness to continue to apply diplomatic and even some economic pressure on Argentina still exists - fears for the lives of thousands of Italians and Argentines of Italian ancestry have been rising in proportion to the escalation of the conflict on the battlefield.

For the smaller countries in Western Europe, including Belgium and the Netherlands, there is ''no question''--as one Belgian official put it--of following the US lead and offering military support to Britain.

At some international meetings recently even neutral Switzerland has been cautioning against backing Britain too far.

Spain--an EC and NATO candidate--has declared its support for Argentina.