Spokesman Greg Burke made the comments while announcing details of the January 15-21 trip to Chile and Peru, Francis' 22nd foreign trip and the sixth to his home continent of South America.
The encounter with two victims of the 1973-1990 Pinochet regime will take place on January 18 in the northern city of Iquique.
Mr Burke was asked if Francis would meet with abuse victims and while he said no meeting was planned, "that doesn't mean it's impossible". He added that such meetings are best when conducted in private.
He said it was "clearly an important theme" in Chile, where the scandal has seriously hurt the Catholic Church's credibility.
Just this week, online database www.BishopAccountability.org said it had found 78 priests or members of religious orders credibly accused or convicted of abuse against minors.
Francis in the past has met in previously unannounced encounters with victims of abuse in the Vatican and in the US, but his record in fulfilling his stated "zero tolerance" for abuse has been questioned by survivors.
While Francis never had to deal with the abuse crisis in his native Argentina, he is intimately familiar with the region's experience with military dictatorships in the 1970s and 1980s.
History's first Latin American pope was in charge of the Argentine Jesuits during the "Dirty War," when thousands of suspected leftists were killed or "disappeared" at the hands of Argentina's military junta.
In neighbouring Chile, after a bloody coup brought General Augusto Pinochet to power, about 40,000 people were killed, tortured or imprisoned for political reasons.
The government estimates that 3,095 were killed, including about 1,200 who were forcibly disappeared.
Francis studied in Chile in 1960 during his novitiate with the Jesuits and counts some of its churchmen as close friends and advisers.
His aim in visiting Chile and Peru is to highlight the plight of indigenous peoples and the delicate Amazon ecosystem.
In keeping with his ecological concerns, he will be travelling around both countries in used popemobiles, rather than have new ones outfitted, as is the norm.
In Chile, the three popemobiles he will ride in were first used during his 2015 trips to the US and Bolivia while his Peruvian popemobiles were shipped from Colombia after his trip there last year, Mr Burke said.
