Interior ministers from West Germany, Italy, Switzerland and Austria met secretly last weekend in Bern, Switzerland, to coordinate border surveillance in the continuing hunt for kidnaped former Italian premier Aldo Moro and to discuss what West Germany security officials are increasingly referring to as "the Swiss problem."

The Germans say there is mounting evidence that fugitive West German terrorists and possibly comrades from other countries, are increasly using neutral Switzerland as a transit point as a possible hideout.

Three weeks ago, West German officials say, thick propaganda booklets from the German Red Army Faction terrorist group began showing up in Swiss border regions telling residents "not to believe the lies of the German murderers," meaning the Bonn Government.

These documents, copies of which are available here, are believed by West German authorities to be the start of an effort by the Red Army group to develop a core of sympathizers willing to help them hide or move about in the German-speaking regions of Switzerland.

The documents also seek to play on possible fears of Swiss residents by claiming that West German "police state methods" are already influencing policy through links between the West German Federal Criminal Office and the Swiss Ministry of Justice.

Swiss Police have been cooperating with West German authorities and have actually apprehended terrorist suspects passing through their country.

Nevertheless, Switzerland remains a relatively easy place to get in and out of these days, and the considerable autonomy of individual Swiss cantons from the federal government also makes it reasonably easy to remain anonymous.

The country borders on West Germany and Italy, both of which have major problems with terrorists, and on France and Austria, both of which have been drawn into the spreading terrorist battleground in Europe.

The massive manhunt in West Germany that followed the kidnap-murder of industrialist Hanns-Martin Schleyer last fall is believed to have caused by German terrorists to flee the country.

Although West German officials do not know for sure where the terrorists have fled and have had little luck catching them, they believe several have gone to Iraq and others are scattered elsewhere in the Middle East, South America, France, Switzerland and northern Italy.

The central importance of Switzerland, officials believe, is the relative ease for getting back into Europe there for terrorists with plenty of money and new identities.

For example, both the West German and Israeli intelligence services, sources here say, are skeptical of reports from Beirut earlier this month that claimed Palestinian guerrilla leader Wadi Haddad - believed to be a key figure in planning numerous airliner hijackings - had died in an East Berlin hospital.

The East German government has never officially commented on this and officials here suspect that they may not have seen the last of Haddad.

The links between the West German terrorists and Palestinians have been well documented in recent years. The fact that the Palestinians have shrinking support in some places in the Middle East these days, however, may be making those areas less hospitable as a refuge for German terrorists. This, combined with the lingering dragnet in West Germany and a new one in Italy, may also be making Switzerland more attractive.

It is also believed that the Communist half of the divided city of Berlin was a way back into Western Europe for terrorists because the Communist officials would not stop them and the borders to West Berlin traditionally are kept open at all. Now, however, West German officials say they are getting reasonably good cooperation in general from Eastern Europe and that the East Germans at leastt are being more attentive than in the past.

Aside from the appearance of the new anti-German documents in Switzerland, there have been other indications of possible terrorist activity there in recent months.

In January, West German officials say, members of the Red Army Faction and the Italian Red Brigades met in Switzerland, and West German police do not rule out a German role in the kidnaping of Moro. In 1977, a woman holding both Italian and German passports, Petra Krause, was extradited from Switzerland to Italy on allegations of supplying arms to both terrorist organizations.

Last December, two other events in Switzerland drew attention to the possible links between the two terror groups.

Two suspected German terrorists. Gabriele Kroecher-Tiedemann and Christian Moeller, were captured in Switzerland heading for the French border after a shootout that left two Swis customs guards wounded. Also, two young Austrians believed to support Red Army terrorists were arrested heading for Italy with forged papers and more than $100,000 in Swiss and American cash.

Both incidents, police believe, were linked to the successful kidnaping in November of Austrian industrialist Walter Palmers by German terrorists who eventually were hidden by Italian extremists. Palmers' family paid nearly $2 million to get him back.

A French intelligence report also calls attention to a murder last month of Swiss policeman Rudolf Heusler in Porrentruy, a town in the Jura region of Switzerland near the French border. A letter found next to the body contained a call to liberate Tiedemann and Moeller.

The intelligence report, which was disclosed by the Swiss newspaper La Suisse, has been confirmed in private by West German authorities.

The newspaper account also said the getaway car used by Schleyer's kidnapers went through Switzerland en route to France and disclosed that a young Swiss police trainee, Rudolf Flukiger, apparently came upon the kidnapers changing cars in the Swiss town of Bure and was killed.His body was taken to France with Schleyer.

Meanwhile, here in West Germany, there has been no sign of the Red Army guerrillas, previously known as the Baader-Meinhof gang since the slaying of Schleyer in early November in France.

Although nine out of 10 Germans said in a recent public opinion poll they still felt that their country was threatened by terrorism, the outward signs of anxiety and extraordinary security have faded.

Millions of posters with the faces of the 20 most wanted terrorists still stare out from billboards all over Germany and Western Europe, promising rewards of close to one-half million dollars.

In West Berlin yesterday, the trial began for six urban guerrillas charged with kidnaping Christian Democrat politician Peter Lorenz and killing West Berlin's chief judge, Guenter von Drenkmann.

Few of the wanted terrorists have been caught, however, and this failure, along with some obvious foul-ups by West Germany's computerized Federal Criminal Office in the Schleyer case, have brought tremendous pressure on the police here, along with demands for more control over autonomous state police forces.

West Germany's chief public prosecutor, Kurt Rebmann, recently warned that the terrorists, armed with a war chest of millions from kidnappings and bank robberies and under pressure to prove that they are still functioning are likely to embark on a new wave of violence.

Privately, however, top security officials admit that they really know nothing. The killers of Schleyer, of former chief prosecutor Siegfried Buback and banker Juergen Ponto are still at large and they are probably in other countries.

Police believe that the death in prison of the three top leaders of the Baader-Meinhof gang has removed the ideological underpinnings from the gang, and the breaking up of a radical lawyer network has deprived it of guidance from others jailed comrades.

But no one is predicting that Rebmann is wrong.