UN High Commissioner for Human Rights Michelle Bachelet has said the decision by the Pre-Trial Chamber of the International Criminal Court (ICC) offers real hope for accountability for the crimes committed against Rohingyas in Myanmar.

"Although the decision doesn't specifically address the crime of genocide, it offers real hope for accountability for the crimes committed," she said addressing the 39th Session of the Human Rights Council in Geneva on Thursday.

The Pre-Trial Chamber of the ICC decided last week that that the court had jurisdiction over the deportation from Myanmar of Rohingya, and possibly other crimes.

In her statement at the high-level panel to commemorate the 70th anniversary of the Convention on the Prevention and Punishment of the Crime of Genocide, she said support for the court is indispensable for both justice and deterrence.

"I urge all States to support the court, and in this, the year we commemorate the 20thanniversary of its founding with the Rome Statute, I call upon all remaining countries to sign or ratify the Statute," said the UN human rights chief in the statement.

Genocide is always shocking but it is never committed without clear, multiple warning signs: a pattern of abuse against a group, intent to harm, a chain of command and finally a brutal and horrifying outcome, Bachelet said.

"In the case of the Rohingya, warning signs abounded: a people oppressed from birth to death, an army answerable to no one, and systematic, state-led human rights violations that went unpunished for decades, including arbitrary deprivation of nationality."

States have the primary responsibility for prosecuting perpetrators, but the court's use is wholly appropriate in cases where the state is unwilling or unable to deliver justice, she said.

The Council's Fact-Finding Mission on Myanmar issued its shocking report on the military-led campaign of murder, rape and assault against the Rohingya people of Rakhine State.

"A conservative estimate of 10,000 dead, countless more bereaved, maimed, raped and traumatised, and nearly three-quarters of a million people forced to flee to Bangladesh."

Accountability matters -- not only because it provides justice for victims and punishment for perpetrators, she said.

"It matters because ending impunity is central to ending genocide. Prevention and punishment -- the explicitly stated twin aims of the genocide convention -- can never be seen in isolation from each other. Punishment is key to prevention. Impunity is an enabler of genocide: accountability is its nemesis."