Guterres said he was "shocked" at reports of General U Min Aung Hlaing's remarks at a military gathering and urged Myanmar's leaders to "take a unified stance against incitement to hatred and to promote cultural harmony."

At the gathering in northern Kachin state on Monday, Hlaing referred to the Rohingya as "Bengalis," a term meant to describe them as foreigners, and said they "do not have the characteristics or culture in common with the ethnicities of Myanmar."

"The tensions were fuelled because the 'Bengalis' demanded citizenship," said the general who was quoted in the Dhaka Tribune.

Some 700,000 Rohingya have been driven into neighbouring Bangladesh since last August by a major army crackdown that the United Nations has likened to ethnic cleansing.

Myanmar authorities say the operation is aimed at rooting out extremists.

Myanmar's de-facto leader Aung San Suu Kyi, a Nobel peace prize laureate, has lost her democratic credentials on the world stage for failing to speak out in favour of the Rohingya.

Guterres said it was "critical that conditions are put in place to ensure that the Rohingya are able to return home voluntarily, in safety and in dignity."

The UN Security Council is hoping to travel to Myanmar to get a first-hand look at the refugee crisis, but has not yet been given the green light for the trip by Myanmar authorities.

Guterres has for months been weighing the appointment of a special envoy for Myanmar that would keep the plight of the Rohingya in the international spotlight.