A cardinal who was sacked from a senior Vatican post by Pope Francis has written his own 'Manifesto of Faith' in the latest attack on the pontiff's authority by a leading member of the Church's conservative wing.

Cardinal Gerhard Mueller, 71, a German who was the Vatican's doctrinal chief until 2017, issued the four-page manifesto on Friday via conservative Catholic media outlets.

He said 'many bishops, priests, religious and lay people' had requested it. He did not say how many and why he was issuing it now.

However, conservatives balked this week when Francis made the first trip by a pope to the Arabian peninsula and signed a Document on Human Fraternity with a Muslim faith leader.

Ultra-conservative Catholics are opposed to dialogue with Islam, with some saying its ultimate goal is to destroy the West.

The manifesto was dated February 10, the sixth anniversary of the eve of former Pope Benedict's announcement of his resignation. Benedict, 91, remains an icon for conservative Catholics.

Mueller said he wrote it 'in the face of growing confusion about the doctrine of the faith'.

He said some Church leaders 'have abandoned the people entrusted to them, unsettling them and severely damaging their faith'. He warned against 'the fraud of (the) anti-Christ'.

Mueller, who did not mention the pope, is one of a handful of conservative cardinals who have open accused Francis of sowing confusion.

They say he is weakening Catholic rules on moral issues such as homosexuality and divorce while focusing excessively on social problems such as climate change and economic inequality.

Their leader is Raymond Leo Burke, 70, an American who was demoted from a senior Vatican position in 2014.

Mueller has ramped up his criticism of the pope since Francis removed him as head of the Vatican's Congregation for the Doctrine of the Faith in 2017.

Most of the manifesto was a re-stating of the Church's teachings, including several that Francis himself has strongly upheld, such as celibacy for priests and the ban on women's ordination.

One section, however, was a clear jab at Francis' reaching out to Catholics who have divorced and remarried outside the Church.

Francis believes some should be allowed to receive communion on a case by case basis, something that is anathema to conservatives.

The Vatican has not commented on the document.