The pontiff, who underwent an intestinal procedure in July, will perform mass in Budapest’s Heroes’ Square to mark the end of a major Catholic conference taking place in the city. Some 75,000 people are expected to attend.
He will also meet Hungarian religious figures and the country’s political leaders. It is a brief stopover ahead of his main four-day sojourn in Slovakia.
The Vatican and trip organisers have stressed that Francis has only been invited to Hungary to celebrate the mass, not make a proper state and pastoral visit as he is doing in Slovakia.
He and Mr Orban disagree on a host of issues, top among them migration, and Francis’ limited stay in Budapest may indicate that he did not want to give Mr Orban’s government the political boost of hosting him for a longer pilgrimage before next year’s general election.
“At the beginning there were a lot who were angry [that Francis wasn’t staying longer], but now I think they understand,” said Reverend Kornel Fabry, secretary general of the conference being held in Budapest.
Rev Fabry noted that a majority of Hungarians backed Mr Orban’s migration policies, “that we shouldn’t bring the trouble into Europe but should help out where the trouble is”.
Mr Orban has frequently depicted his government as a defender of Christian civilisation in Europe and a bulwark against migration from Muslim-majority countries.
Francis has expressed solidarity with migrants and refugees and criticised what he called “national populism” advanced by governments like Hungary’s. He has urged governments to welcome and integrate as many migrants as they can.
Mr Orban’s government has also passed a law that prohibits the depiction of homosexuality in education settings. Francis has previously indicated he is accepting of homosexuality on an individual level.
About 39 per cent of Hungarians declared themselves to be Roman Catholic in a 2011 census, while 13 per cent declared themselves to be Protestant, either Lutheran or Calvinist, a Protestant branch with which Mr Orban is affiliated.
Additional reporting by Associated Press