Ban spoke while standing next to Foreign Minister Wang Yi, who last month berated a Canadian journalist for asking a question about China's human rights record during a news conference in Canada.
"As China continues along the path of transformation and reform, I encourage China's leaders to create the space needed for the civil society to play its crucial role," Ban said, as Wang looked down at his lectern or stared ahead, expressionless.
"Along with a free and independent media they can help ensure accountability, thereby helping the state to evolve better and strengthening its standing in the eyes of the people," Ban said during the tightly managed news conference, in which only two questions were allowed.
While China's news media have long been directed by the ruling Communist Party, President Xi Jinping signaled a further tightening of control in February when he stated that absolute loyalty to the party was the media's highest priority.
Ban, whose second term as UN secretary-general runs out at the end of the year, said, "The world will look to China to complement its remarkable economic progress by giving citizens a full say and a role in the political life of their country."
The pair also discussed tensions involving the South China Sea ahead of a ruling expected next week by an international arbitration panel on the validity of China's claims to virtually all of the sea. Beijing has not participated in the case, which was brought by the Philippines.