The Vatican has sought to tamp down discord over Pope Francis' backing last month for same-sex civil unions, reiterating that he did not question the Catholic dogma of marriage being between a man and a woman.

A note sent to papal ambassadors late last week by the Secretariat of State -- the Vatican's highest bureaucratic authority -- hammered home that there had been no change in Church doctrine.

"It's clear that Pope Francis was referring to certain arrangements by states, certainly not to Church doctrine, which has often been reaffirmed over the years," the authority said in the document, published by envoy to Mexico Archbishop Franco Coppola among others.

Italian Catholic newspaper Avvenire reported that the letter had been intended for circulation to bishops around the world.

In a documentary that premiered at the Rome Film Festival last month, Francis stunned many with his comment that gay couples should be allowed to have legally recognised civil unions.

"These are children of God, they have the right to a family," the Argentine pontiff said. "What we have to create is a law of civil union, they have the right to be legally protected."

Pope Francis
Francis' remarks backing gay civil unions came as a surprise to some Catholics. Photo: VATICAN MEDIA / -

The quotes shown in a film by documentarist Evgeny Afineevsky were originally recorded as part of an interview Francis gave to a Mexican journalist in 2019, but had never before been shown.

Their release sparked fears among some traditionalists that the pope might in fact favour gay marriage.

Ultra-conservative German cardinal Gerhard Mueller -- a former Vatican head of dogma retired by Francis in 2017 -- said he had received calls from "disturbed" fellow Catholics.

"The pope is not above God's word," he told Italian daily Corriere della Sera the day after the documentary was released.

Catholics could not recognise gay civil unions because they could represent a "first step" towards gay marriage, Mueller added.

In its note to ambassadors, the Vatican argued that the documentary makers could have "caused confusion" by editing out the questions Francis had been asked.

Elsewhere, the pope has said that "always among human beings, and not only in the Church, (marriage) has been between a man and a woman. You can't just change that like that."

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