The top United Nations envoy to Myanmar says the country's Rohingya Muslims must have a path to citizenship, otherwise their security will remain under threat.

Vijay Nambiar, in a speech to the International Peace Institute on Thursday, also said that if such a step were not taken "it would affect the international reputation of the country".

Myanmar sees Rohingya Muslims, who live in Rakhine state, as illegal immigrants from Bangladesh even though many were born to families who arrived in the country generations ago.

The million-plus population does not officially exist on government records and the government has said the community is barred from a national census unless its members identify themselves as Bengali. 

A report from a human rights group published in February claimed that state policies restricted the Rohingya's "movement, marriage, childbirth, home repairs and construction of houses of worship".

Earlier this month, another UN envoy said severe shortages of food, water and medical care for Rohingya Muslims in western Myanmar were part of a long history of persecution against the religious minority that could amount to "crimes against humanity".

Tomás Ojea Quintana's statement followed the evacuation of hundreds of international humanitarian workers from Rakhine.

Myanmar has also faced criticism from US President Barack Obama, who last month said the country could move in a "very bad direction" if people were politically organised around their religious or ethnic identity.

Source: AP