A Vatican-affiliated university has hosted an international campaign to ban surrogacy, with an official calling for an alliance that goes beyond Catholics to stop the "depersonalisation" of life.

The two-day conference at Lumsa Catholic university in Rome, which ended on Saturday, was organised by the movement behind the Declaration of Casablanca, a treaty signed in 2023 by 100 anti-surrogacy campaigners.

Critics of surrogacy say it "violates human dignity and contributes to the commodification of women and children" both for commercial arrangements and "altruistic" ones.

"Surrogacy induces depersonalisation", Miroslaw Wachowski, the Vatican's Under-Secretary for State Relations, told the conference.

"It is important to avoid giving the impression that this is a Catholic battle.

"To achieve an international ban, we need a broad front of agreement," he said, according to the Vatican News official media outlet.

Italy's main gay family advocacy group, Rainbow Families, responded by saying fears over "the buying and selling of children" did not take into account "altruistic" surrogacy.

Pope Francis called in January for a global ban on surrogacy, saying the practice of a woman carrying another person's child was "deplorable".

The 87-year-old pontiff said it was a "grave violation of the dignity of the woman and the child".

The conference came as Italy's hard-right government plans to make it a crime for Italians to use surrogates abroad. The practice is already illegal in Italy.

Gay family group Rainbow Families, organised a pro-surrogacy rally on Friday.

"They are our children from the moment they are born," Cristiano Giraldi, a 45-year-old father of twins born through surrogacy, told AFPTV.

"We are a family like many others", he said, adding that fears over "the buying and selling of children" did not take into account "altruistic" surrogacy.

"Altruistic" surrogacy, whereby a woman gives birth to a baby on behalf of another woman or couple but no money changes hands, excluding for expenses, is legal in countries including Belgium, Brazil, Canada, Colombia, the Netherlands and the UK.

Commercial surrogacy is permitted in some US states.

Francis met privately on Thursday with one of the campaigners calling for a universal ban on surrogacy, French activist and 32-year-old mother of three Olivia Maurel, Vatican News said.

Maurel, who was born via surrogacy, said there was a "rapidly expanding business worth 14 billion euros worldwide in 2022 alone", the Vatican News cited campaigners with the Casablanca Declaration as saying.

She blames her "psychological fragilities" as a teenager on not having been allowed to breastfeed from the woman who carried her in her womb, and being placed in an incubator straight after birth, Vatican News added.

In June 2022, the pope condemned surrogacy as an "inhuman" practice.

The Vatican is set to reaffirm its position on Monday with a new paper on "human dignity", which is expected to insist that human life should only be created through intercourse between a husband and wife.