A Myanmar Buddhist monk who called a UN human rights envoy a "whore" has violated his monastic code and could damage his religion, another prominent monk says, but he is unlikely to face censure.

Ashin Wirathu denounced Yanghee Lee, the UN special rapporteur on human rights in Myanmar, in a speech in Yangon on Friday, after she questioned draft laws that critics said discriminate against women and non-Buddhists.

"Just because you hold a position in the United Nations doesn't make you an honourable woman," Wirathu told a cheering crowd of several hundred people in Yangon on Friday.

"In our country, you are just a whore."

The monk also accused Ms Lee of bias towards Rohingya Muslims, a stateless minority in the western Myanmar state of Rakhine.

"You can offer your arse to the kalars if you so wish but you are not selling off our Rakhine State," he said.

Kalars is a derogatory word for people of South Asian descent.

His speech was condemned by Thawbita, a leading member of the progressive Saffron Revolution Buddhist Monks Network in Mandalay, where Wirathu is also based.

"The words used that day are very sad and disappointing," Thawbita said.

"It is an act that could hurt Buddhism very badly."

The network was formed by monks who helped lead the 2007 Saffron Revolution, a nationwide democracy uprising brutally crushed by the military.

It is influential among educated Buddhists, but has little power.

A senior official at the ministry of religious affairs said there were no plans to act against Wirathu.

"Of course, he has the right to express his opinion but he shouldn't have used these terms," the official said, who requested anonymity due to the sensitivity of the issue.

"It can tarnish the image of our religion among those who don't really understand its essence."

Famed for his fiery speeches, Wirathu belongs to a radical anti-Islamic group whose monks preach that Muslims will one day overrun Myanmar.

Buddhism is the country's predominant religion and its monks are revered.

A quasi-civilian government now runs Myanmar after nearly half a century of hardline military rule.

But its reforms have been marred by deadly religious clashes, with rights activists warning that hate speech could lead to further violence.

Ms Lee responded indirectly to Wirathu's remarks in a statement released by her office on Monday.

"During my visit I was personally subjected to the kind of sexist intimidation that female human rights defenders experience when advocating on controversial issues," she said.

Reuters