"While the secretary-general notes the clear recognition at the highest political levels in Myanmar of the need to contain this communal violence, he calls on the authorities to take urgent and effective action to bring under control all cases of lawlessness," spokesman Martin Nesirky said in a statement released Friday by the United Nations.
Ban said recent outbreaks of violence in five townships in Rakhine state were "deeply troubling."
Government officials have said at least 56 people had been killed and hundreds of homes set on fire since Sunday in Rakhine state in western Myanmar, formerly known as Burma.
In June, clashes between ethnic Rakhine Buddhists and Rohingya Muslims led the Myanmar government to declare a state of emergency in the area.
"The widening mistrust between the communities is being exploited by militant and criminal elements to cause large-scale loss of human lives, material destruction, displaced families as well as fear, humiliation and hatred affecting the people from all walks of life," the statement made on Ban's behalf said.
Ban called for an end to vigilante attacks, targeted threats and extremist rhetoric, warning that if nothing is done, "the fabric of social order could be irreparably damaged and the reform ... being currently pursued by the government is likely to be jeopardized."