Passau, Germany - The Catholic church sees the faithful leaving the church in droves after the controversial lifting of the excommunication of a group of rightist bishops, a German Vatican expert said Saturday.

Father Eberhard von Gemmingen, the head of Radio Vatican's German service, said in an interview with the Passauer Neuen Presse newspaper that a new "wave of exits" had already set in after Pope Benedict XVI lifted the excommunication of four leaders of the St Pius X Society, one of whom denies the Holocaust.

In Germany, Austria and Switzerland Catholics have the option of formally quitting the church by registering their exit with local authorities. They are then no longer considered Catholic.

"In other countries this is not possible, as baptism cannot be revoked," Gemmingen said.

The relationship of trust between the German-born pope and German catholics has been "shaken," Gemmingen said, but believed Benedict XVI's planned visit to his home country next year could repair some of the damage.

"It hurts if you see that many people do not understand Rome and the pope any longer," the Vatican expert said and also voiced scepticism whether the head of the Catholic church would go ahead with his planned visit to Israel this year.

"If it really happens is still very open," he said, while indicating there had been no adverse signals from the Jewish state.

Benedict XVI, former Cardinal Joseph Ratzinger, had lifted the excommunication of Holocaust-denier Richard Williamson and three other bishops of the St Pius X Society, a move which triggered criticism within the church and an outcry in his German homeland, including sharp remarks form Chancellor Angela Merkel.

According to an opinion poll by state broadcaster ARD, only 42 per cent of Germans approve of his work, down from 63 per cent when Ratzinger took office four years ago.

Amid growing pressure, a statement was eventually issued in which the Vatican said that the British-born Williamson would have to recant his Holocaust-denial claims before being allowed to occupy any office within the church. The St Pius X society broke with the Vatican over church remors made in the 1960s.

Gemmingen sharply criticized the Vatican's communication blunders during the affair. "There is not only a communication problem. But also an organization problem. Decisions cannot not be made without involving those responsible for the issues in the Vatican."

There had to be better information, and decisions made jointly, he argued. "But in the Vatican communication will change only very slowly and very little." (dpa)