Testifying at a parliamentary hearing on the case Monday, Mr. Fischer took responsibility for lax visa policies that allowed what opposition politicians say was an influx of pimps, prostitutes and drug dealers from eastern Europe to enter Germany.
But the foreign minister says his opponents are wildly exaggerating the dimensions of the scandal. And he says official government statistics show no rise in crime by eastern European immigrants.
In the year 2000, the foreign ministry eased rules granting tourist visas from eastern Europe, and that spurred an influx of people from countries that belonged to the former Soviet Union, mainly Ukraine. The opposition charges that Mr. Fischer ignored warnings from law enforcement officials and his own diplomats about the consequences of the policy.
Some of those granted tourist visas turned out to have been criminals and women who were forced into prostitution in Germany. The relaxed visa rules also allowed workers seeking illegal employment to enter a country already suffering from a jobless rate of more than 10 percent.
Radio commentator Alan Posener, who has written a biography of Mr. Fischer, says the public perception that the foreign minister dithered in taking responsibility for the scandal has undermined his popularity.
"During the period of 2000 to 2004, there was virtually no control in [Germany's] eastern European consulates about who got to get a visa to come to Germany," he said. "This was not controlled there by the consulates. Basically, anyone who presented any kind of invitation was allowed in. And it certainly was not controlled here in Berlin. And the political responsibility is borne by Mr. Joschka Fischer, our foreign minister."
Even though the visa rules in question are no longer in effect, members of parliament representing the opposition Christian Democrats, like Andreas Schokenhoff, are demanding that Mr. Fischer should consider stepping down because it was he who issued the directive to relax the policy on visas.
"Joschka Fischer personally signed that order, and, if the inquiry proves that he knew about the massive abuse, then he has to resign," he said.
The questioning of Mr. Fischer by the parliamentary committee, which was broadcast live on German radio and television, comes at a bad time for Chancellor Gerhard Schroeder's left-of-center government, which faces a key state election next month. If the coalition between Mr. Schroeder's Social Democrats and Mr. Fischer's Green Party loses that contest, it could spell trouble for its efforts to hold on to power in national elections next year.