“I am not saying that they must be lifted, but they must be analysed in detail,” said UN special rapporteur on Myanmar, Tomas Ojea Quintana.

This is “because they are a human rights issue,” added Quintana during a press conference after presenting his report on the situation in Myanmar to the UN Human Rights Council.

“I really believe that sanctions have to do with human rights, in different areas, particularly in economic, social and cultural rights. Because of that, we have the responsibility to address it publicly, openly, not just as a carrot” for reforms, he added.

The European Union, United States and other Western nations this year started easing sanctions on Myanmar in recognition of recent positive moves toward political reform after decades of direct military rule.

Washington’s partial lifting now allows it to support assessment missions and limited technical assistance in Myanmar by bodies such as the World Bank, Asian Development Bank and International Monetary Fund.

The 27-nation EU meanwhile lifted travel bans against the nation’s leaders as a first step in January, while pledging further action if there were continued change.

At stake are embargos on arms deliveries, logging and mining, the resumption of aid, and unlocking assets of more than 900 firms and utilities.

Quintana, who visited Myanmar in February, noted that recent reforms have had a positive impact but that serious human rights concerns remain.

The concerns “cannot be ignored in the rush to reform and to move forward,” said the UN rapporteur, pointing to the “lack of an independent, impartial and effective judiciary” to uphold the rule of law.

Discrimination against ethnic minorities also persists, said Quintana, stressing that guaranteeing respect for their rights was “essential for national reconciliation” and for long-term social and political stability.

The credibility of April 1 by-elections “will not be determined solely on the day of the vote, but on the basis of the entire process leading up to and following election day,” said Quintana.

A nominally-civilian government came to power in Myanmar last year after controversial November 2010 elections and has since surprised observers with a number of positive moves including a major release of political prisoners.

It has also made efforts to seek peace with ethnic rebel fighters and dialogue with the opposition, notably pro-democracy icon Aung San Suu Kyi.