"The process of healing also needs to include the pursuit of truth," said the pope, whose visit will focus on reconciliation in a country still recovering from a 37-year ethnic conflict that pitted Tamil separatists against government troops.
"All members of society must work together; all must have a voice. All must be free to express their concerns, their needs, their aspirations and their fears."
Pope Francis said the work of rebuilding after the conflict must include respect for human rights -- a hugely contentious issue in Sri Lanka, which has alienated the international community by refusing to cooperate with a UN-mandated investigation into alleged wartime killings of civilians.
"The great work of rebuilding must embrace improving infrastructures and meeting material needs, but also, and even more importantly, promoting human dignity, respect for human rights, and the full inclusion of each member of society," said the pope, who spoke in English.
He was greeted at Colombo's main airport by the country's new President Maithripala Sirisena, who took office only days ago and has promised an independent domestic inquiry into the allegations of wartime rights abuses under his predecessor Mahinda Rajapakse.