Pope Francis has rejected German Cardinal Reinhard Marx's offer to resign as archbishop of Munich over the Church's sexual abuse crisis, a letter released by the Vatican showed.

Cardinal Marx, one of the Catholic Church's most influential liberalf igures, offered to resign earlier this month, saying he had to share responsibility for the "catastrophe" of sexual abuse by clerics over past decades.

Pope Francis said he understood the motivation behind the cardinal's offer to resign, but would not accept it.

"That is my answer, dear Brother. Continue as you suggest, but as Archbishop of Munich," the pontiff worte in the letter.

A former head of the Catholic Church in Germany, Cardinal Marx is not under any suspicion of having participated in abuse or cover-ups.

The Church is investigating abuse allegations in another German archdiocese, Cologne, after a report in March found hundreds of victims there.