An unprecedented 200,000 child refugees have fled Burma and are now in urgent need of help, the United Nations Children's Fund (UNICEF) has warned, as the Rohingya crisis reaches new proportions.

Minors make up at least 60 percent of the 330,000 Rohingya who have crossed the border to Bangladesh over the past few weeks. 

Highly traumatized, they are arriving malnourished and injured after walking for days, The Independent reported. 

Quoted by The Independent, UNICEF communications chief for south Asia Jean-Jacques Simon said it was hard to imagine what the "streams" of people crossing had witnessed.

"It's reaching a new proportion every day... You have to wonder when it will stop," he said.

Simon said he had seen children as young as three arrive in Bangladesh without their parents. 

"Was it because the parents put them forward for the crossing, or was it something else?" he asked.

This comes after the United Nations Secretary-General António Guterres on Wednesday reiterated his call for Muslims from Myanmar's Rakhine state to be granted nationality or at least a legal status that would allow them to lead a normal life, while also urging the international community to help provide assistance for the nearly 380,000 people who have fled to Bangladesh.

“I call on the Myanmar authorities to suspend military action, end the violence, uphold the rule of law, and recognize the right of return of all those who had to leave the country,” the Secretary-General said in his first press conference since the opening of the 72nd session of the General Assembly.

Guterres repeated his call for “an effective action plan” to address the root causes of the situation, which he said had been left to fester for decades and has now escalated beyond Myanmar's borders, destabilizing the region.

The Security Council was due to discuss the situation on Wednesday in an urgent closed-door meeting, following an official letter from the Secretary-General expressing his concern.

“The humanitarian situation is catastrophic,” he said, noting that at the time of his briefing to the press last week, there were 125,000 Rohingya who had fled to Bangladesh. That number has now tripled to nearly 380,000 and people are arriving hungry and malnourished and finding shelter in makeshift settlements or with host communities.

“I urge all countries to do what they can for humanitarian assistance to be provided,” Guterres said. He also called on Myanmar authorities to ensure delivery of aid by UN agencies, non-governmental organizations and others.

The humanitarian community has this week launched a $77 million USD appeal to aid some of the stateless refugees for the next three months.

This came just a day after Myanmar's de facto leader Aung San Suu Kyi called off plans to attend the UN General Assembly session in New York amid growing outrage over the unfolding Rohingya crisis.

Critics have called for the Nobel laureate to be stripped of her peace prize amid reports of “ethnic cleansing” against Rohingya Muslimse.

Her spokesman said Tuesday State Counselor Aung San Suu Kyi will focus attention on the "Rakhine terrorist attacks," and will not attend the UN session.