Franz Josef Strauss, the Bavarian state premier renowned in West Germany for his strident criticism of Communist states, became one of detente's most unusual converts by meeting today with East German leader Erich Honecker.

Strauss, who is on a private trip through Poland, East Germany and Czechoslovakia, joked and laughed with Honecker in front of photographers before the two men withdrew for private discussions at an old Prussian hunting lodge 35 miles north of Berlin.

Following the talks, Strauss told reporters he was convinced that the prospective deployment of new nuclear missiles in West Germany later this year would not adversely affect relations between the two states.

But Honecker was quoted by the official East German news agency as warning that the U.S.-built missiles could have a negative effect not only on West German interests but also on relations between the two Germanys.

Strauss' encounter with Honecker and his tour through Eastern Europe represent the latest signs of his startling conversion from cold war rhetoric to a desire to nurture more pragmatic contacts with Warsaw Pact countries.

Only three months ago, Strauss angrily denounced the East Germans as "murderers" after a West German citizen died of a heart attack while being questioned by East German border guards.

On June 30, four days before Chancellor Helmut Kohl visited Moscow, the Bonn government announced that it would guarantee a $400 million credit to East Germany.

The loan was the largest ever offered by West German banks to East Germany and was perceived as a shrewd gesture to insulate relations between the two Germanys from more turbulent East-West tensions if Geneva arms talks fail to prevent deployment of new nuclear missiles later this year.

Following Kohl's return from the Soviet Union, Strauss revealed that he had engineered the loan by arranging the terms with East German officials and persuading Bavarian banks to serve as the prime sources of the money.

The news stunned right-wing supporters in Strauss' Christian Social Union, the Bavarian sister party of Kohl's Christian Democratic Union. Some irate members called for his immediate resignation as party leader.

Strauss, however, seemed to relish the controversy he had generated and twitted reporters for casting him as a rigid conservative.

"I can change corners faster than your eyes can follow," he said with a grin. "I don't stand on principle when I have strong convictions."

While in Poland, Strauss told an interviewer that the end of martial law there and the passage of new legal restrictions were "a step in the right direction."

He also said that the time has come for the Bonn government to cease subsidizing food parcels sent to Poland.

Chancellor Helmut Kohl, however, seems to have reaped the greatest political dividends from Strauss' remarkable change in behavior.

Kohl has been eager to find ways to protect inter-German relations from the anticipated troubles in East-West relations caused by the likely deployment of new intermediate-range missiles in West Germany, Britain and Italy beginning in December.

By announcing the loan just before his trip to Moscow, Kohl demonstrated that West Germany's economic strength remains a vital crutch for East Germany, which, like other Soviet Bloc countries, suffers from a shortage of hard currency to service foreign debts and pay for necessary imports.

By encouraging Strauss to take the leading role in establishing the loan and meeting with Honecker, Kohl successfully shielded his flank from a barrage of right-wing criticism within his party.

Strauss has admitted that the loan was granted without any assurances of concessions from East Germany. In the past, Strauss denounced the practice of unilateral loans to the East carried out under former chancellor Helmut Schmidt's government as "utter stupidity."

As an opposition leader, Strauss often argued that West Germany should sever its financial aid unless East Germany reduced the sum of 25 marks ($10) per day that each West German must exchange when traveling to the East.

The rates have become prohibitive for many West Berlin pensioners.

After his meeting today with Honecker, Strauss called the minimum exchange requirement "an onerous measure" but gave no indication whether the East Germans were now willing to reduce the amount.