Germany's Constitutional Court in Karlsruhe said the current law that allows authorities to eavesdrop on conversations in private homes was unconstitutional and must be rectified by June 2005.

Three politicians from Germany's small FDP party had brought the complaint, even though the liberals were part of former Chancellor Helmut Kohl's government when the law was passed six years ago.

Aiming to fight organized crime and terrorism, it was highly controversial at the time, because of the country's history of the Nazi police state, and following decades of surveillance by the East German secret police, the Stasi.

However, FDP politicians Sabine Leutheusser-Schnarrenberger, Gerhart Baum und Burkhard Hirsch opposed the law on the grounds that it violates constitutional privacy guarantees, and that it hasn't helped solve any major cases.

New rules

According to the latest ruling, bugging of phones in private homes should only be allowed in cases where there is a suspicion of a serious offense that could carry a prison sentence of more than five years. Up to now, phone surveillance was allowed in the case of offenses that carried lesser sentences.

In addition, surveillance must be immediately cut when the conversation is clearly of a private nature, or when people under surveillance are speaking in their homes to close relatives, doctors, priests or defense lawyers who are not themselves suspects.

The court's decision argues that the protecting private homes is part of protecting human dignity, and that only surveillance that protect human dignity should be permitted.

"It is not necessarily a violation of human dignity if someone is put under observation," court justice Hans-Juergen Papier said, according to a report by the Associated Press. "But in such cases, the core area of privacy must be safeguarded."

The German government says eavesdropping is used only as a last resort. Overall, authorities plant bugs in homes in about 30 cases a year.