The persecution of Rohingya by Myanmar's security forces may amount to genocide, the UN human rights chief Zeid Ra'ad al-Hussein has said.

Addressing the Human Rights Council on Tuesday, Zeid said UN investigators have received "concordant reports of acts of appalling barbarity committed against the Rohingyas" during a military crackdown in Rakhine state in August.

These included allegations of security forces "deliberately burning people to death inside their homes, murders of children and adults; indiscriminate shooting of fleeing civilians; widespread rapes of women and girls, and the burning and destruction of houses, schools, markets and mosques", he added.

"Given all of this, can anyone rule out that elements of genocide may be present?"

Zeid urged the 47-member council to recommend to the UN General Assembly to authorise a new mechanism to probe individual criminal responsibility.

Myanmar's government has denied allegations of ethnic cleansing and crimes against humanity, but it has refused UN investigators and journalists access to the affected areas in northern Rakhine state.

The military said its actions were legal and in response to coordinated attacks on border posts by a Rohingya armed group. Those who fled the violence did so voluntarily, some officials have said.

Zeid said some about 626,000 Rohingya have fled since August, and many more are continuing to pour into Bangladesh.

Myanmar and Bangladesh signed a repatriation deal in November, but little is known of its provisions.

But Zeid said no Rohingya refugee should be repatriated without sustained human rights monitoring to ensure they can live safely and in dignity, warning that continued dehumanising of the Muslim minority could fuel further violence and draw in other communities.

Amnesty International has called on the Human Rights Council to pass a "strong resolution that sends a clear message to Myanmar's government and military that their abhorrent treatment of the Rohingya must end immediately".

PHOTO CAPTION

Rohingya refugee Kalabarow, 50, poses for a photograph at Leda refugee camp, in Bangladesh, October 15, 2017. Reuters

Al-Jazeera