Presenting the document at a news conference in Rome, the cardinal said that theologians were "manipulating and going beyond the limits of tolerance when they put all religions on the same plane".
In a highly controversial document published on Tuesday, the Roman Catholic Church reaffirmed its belief that it is the only true one, and that other Christian communities such as Protestants are not Churches in the proper sense of the word.
The document has provoked a storm of criticism, particularly from members of the Anglican Church, who see it as undermining the progress of recent years towards dialogue between different religions.
'Wound for Church'
The 36-page document, called Dominus Iesus, was written by Pope John Paul II's chief expert on doctrine, Cardinal Josef Ratzinger, although it was approved and signed by the Pope himself.
Presenting the document at a news conference in Rome, the cardinal said that theologians were "manipulating and going beyond the limits of tolerance when they put all religions on the same plane".
The document ruled out "a religious relativism which leads to the belief that 'one religion is as good as another'".
It also said that other Christian communities, such as Anglicans or Protestants which broke away from the Vatican during the Reformation, "are not Churches in the proper sense".
It stated that non-Christians were "in a gravely deficient situation" with regard to salvation and that even other Christian Churches had defects partly because they did not recognise the primacy of the Pope.
And it conceded that "the lack of unity among Christians is certainly a wound for the Church".
Pope's sorrow
Correspondents say the document could set back much of the progress achieved by the Pope who has made inter-religious dialogue one of his main goals.
During a visit to Israel, the Pope made conciliatory moves towards the Jews, expressing sorrow for a history of anti-Semitism in the Roman Catholic Church.
Britain's Chief Rabbi, Jonathan Sacks, said he feared the new document might undo much of this good.
The Archbishop of Canterbury, spiritual leader of the Anglican Church, was quick to declare that he did not believe his Church was deficient in any way.
Conservative Roman Catholics argue that the church can hardly be expected to deny its own supremacy or it would abandon much of what it has stood for 2,000 years.
But correspondents say that the allegedly negative tone of the document sits uneasily in the more liberal, democratic atmosphere of the 21st century.