Vatican City — The Pope kept up his campaign against gay marriage Saturday, telling the ambassador from Canada — where it is legal in some provinces for same-sex couples to wed — that such unions create a “false understanding” of marriage.

In past months, the Pope urged authorities to stop approving gay marriages, saying that they degrade the true sense of marriage.

The Pope spoke Saturday to the new Canadian Ambassador to the Vatican, Donald Smith.

“The institution of marriage necessarily entails the complementarity of husbands and wives who participate in God's creative activity through the raising of children,” said the pontiff, according to the text of the speech released by the Vatican.

“Spouses thereby ensure the survival of society and culture, and rightly deserve specific and categorical legal recognition by the State.

“Any attempts to change the meaning of the word 'spouse' contradict right reason: legal guarantees, analogous to those granted to marriage, cannot be applied to unions between persons of the same sex without creating a false understanding of the nature of marriage.”

Three Canadian provinces, accounting for about 70 per cent of the country's 31 million people, allow same-sex marriage: Quebec, Ontario and British Columbia. The ruling Liberal Party has promised legislation legalizing gay marriage, perhaps next year after Canada's Supreme Court gives a non-binding opinion on a tentative bill.

Speaking to another newly appointed ambassador to the Vatican, Philip McDonagh of Ireland, the Pope called on the European Union to keep a policy of openness and acceptance of immigrants. Ireland held the EU rotating presidency until the end of June.

“The plight of refugees and those displaced by poverty, war or persecution is particularly dramatic and calls for special consideration and generosity,” the Pope said.

“The Holy See hopes that the steps taken during the Irish presidency of the European Union in favour of policies of openness to other peoples will continue to inspire the community's attitude to immigrants from other continents and cultures.”