Geneva: Myanmar may be using bureaucratic means to get rid of its Rohingya Muslim minority after a security crackdown against them caused an international outcry, the U.N. human rights investigator on Myanmar said on Monday.

The U.N. human rights office said last month that the campaign of killings and rapes probably amounted to crimes against humanity and possibly ethnic cleansing.

U.N. special rapporteur Yanghee Lee told the U.N. Human Rights Council that Myanmar was still making Rohingyas' lives difficult by dismantling homes and conducting a household survey.

"Conducting a household survey - where those absent may be struck off the list that could be the only legal proof of their status in Myanmar - indicates the government may be trying to expel the Rohingya population from the country altogether. I sincerely hope that that is not the case," she said.

Myanmar's military launched the crackdown in the north of Rakhine state after nine policemen were killed on Oct. 9. Some 75,000 Rohingya have since fled to Bangladesh, where Lee said she had heard "harrowing account after harrowing account".

"I heard allegation after allegation of horrific events like these – slitting of throats, indiscriminate shootings, setting alight houses with people tied up inside and throwing very young children into the fire, as well as gang rapes and other sexual violence," she told the Council.

Lee visited Myanmar twice in the past year, including Rakhine state. But she was blocked at the last minute from Kachin state, another area of ethnic violence.

"I must confess that there were times that I had seriously questioned the nature of the cooperation," she said.

Myanmar's ambassador Htin Lynn called the allegations of crimes against humanity unverified and one-sided. He said security operations in Rakhine had stopped and the curfew was eased earlier this month.

"The situation in Rakhine state is very complicated in nature and thus requires complicated answers. It also requires greater understanding by the international community," he said.

Human rights challenges could not be solved within a year, he said, referring to the year-old government led by Aung San Suu Kyi. But Lee said Myanmar's number of political prisoners had doubled to 170 in that time.

U.N. human rights chief Zeid Ra'ad al Hussein has said treatment of the Rohingya merits a U.N. commission of inquiry and review by the International Criminal Court.

But Myanmar is unlikely to face international scrutiny because a Human Rights Council resolution drafted by the European Union would leave the country itself to investigate.