Human rights abuses are still going on in Burma, according to the United Nations, despite reforms made by the military-backed government.
The UN has singled out the arbitrary arrest and torture of alleged ethnic Kachin rebels.
Tomas Ojea Quintana, U.N. special rapporteur on the human rights situation in Myanmar, was speaking at the end of a five-day mission to the country, where President Thein Sein has pushed through reforms since the end of military rule in 2011.
"While this process of reform is continuing in the right direction, there are significant human rights shortcomings that remain unaddressed," Mr Quintana told reporters, calling for urgent action before the problems became entrenched.
The quasi-civilian government has agreed ceasefires with most of the ethnic rebel groups fighting for autonomy. But fighting flared up in Kachin State in June 2011 and the conflict escalated late last year when the military used air strikes to thwart what it said was rebel aggression.
Peace talks were held over the border in China this month and Quintana said he was encouraged by this. He also welcomed the government's decision to allow a U.N. humanitarian convoy access to areas controlled by the rebels.
But he added: "I am concerned about the ongoing practice of arbitrary arrest and torture during interrogation by the military of Kachin men accused of belonging to the Kachin Independence Army."
Another area, Rakhine State, suffered two bouts of deadly sectarian violence last year between ethnic Rakhine Buddhists and Muslim Rohingyas.
Around 120,000 people are now living in camps, according to Mr Quintana. Although conditions had improved since his last visit in August, there was still a lack of adequate healthcare in the bigger Muslim camps, he said, adding that harassment of medical staff by Rakhine Buddhists was one of the reasons.
The government needed to address the problem of freedom of movement in the camps, he said, noting that one "felt more like a prison than a camp".
The government says the Rohingyas are illegal immigrants from Bangladesh and does not regard them as citizens. Bangladesh also denies them citizenship and the estimated 800,000 Rohingyas in Rakhine State are therefore effectively stateless.
Mr Quintana said the two communities remained divided by fear, distrust, anger and hatred.
"Mutually respectful dialogue cannot be had while discrimination based on grounds of ethnicity and religion remains unaddressed," he said, recommending that the government amend citizenship laws to end such discrimination.