Francis is to begin a three-day visit on January 13, five days after the poll. Some church officials are seeking a postponement, fearing there could be post-election violence because of the acrimonious campaign.
President Mahinda Rajapaksa, who is seeking a third term in office, is facing his former health minister, Maithripala Sirisena. Sirisena defected from Rajapaksa's government after the election was announced last month.
Cardinal Malcolm Ranjith said the bishops' conference met with both candidates and received their assurances of no violence, the Catholic weekly newspaper Messenger reported on its website.
About 70 per cent of Sri Lanka's 20 million people, including both main candidates, are Buddhist. Roman Catholics number about 1.2 million.