"Myanmar's National Human Rights Commission has failed to address the allegations," Tomas Ojea Quintana, the UN special envoy on human rights to Myanmar, said at the end of his ninth and final visit to the country.
The United Nations last month called on Myanmar to set up an independent and impartial commission to investigate the reported killings of about 50 Rohingya villagers January 9-13 in Maungdaw in the western state of Rakhine.
The government of Myanmar denied the reports but tasked its National Human Rights Commission with investigating.
"There is no evidence to confirm the information of a massacre in this village," the commission concluded Friday after visiting the area.
Quintana said the investigation should comply with international standards.
"I call again on Myanmar's government to set up an independent and impartial investigation commission," he said at Yangon Airport before his departure.
Quintana, who was on his last tour of Myanmar as a special envoy, visited refugee camps in the Rakhine and also met with representatives from the largest party in the state, the opposition Rakhine Nationalities Development Party, and leaders from both the Buddhist and Muslim communities.
Rakhine saw an outbreak of clashes between Buddhists and Rohingyas in 2012, which left at least 167 people dead and more than 140,000 homeless.