Tomas Ojea Quintana, the U.N. special envoy on the rights situation in Myanmar, said there were significant gaps in Myanmar's reform measures.
"While the process of reform is continuing in the right direction, there are significant human rights shortcomings that remain unaddressed," he said Monday in a report to the U.N. Human Rights Council.
He singled out Myanmar's response to ethnic clashes in Rakhine state and fighting with separatist elements from Kachin state last year. Combined, nearly 200,000 people have been displaced by conflict in Myanmar.
Human Rights Watch said Monday it was calling on Myanmar to work more closely with the United Nations while at the same time working domestically to address lingering political, media and civil rights concerns.
"The (Human Rights) Council should not let the government sweep the issue of minority rights under the rug," Juliette de Rivero, Geneva director at Human Rights Watch, said in a statement.
Myanmar embarked on democratic reforms that gained momentum following general elections in 2010.