The lack of humanitarian access granted by Myanmar's government to Rakhine state, where more than half a million Rohingya Muslims have fled violence, is "unacceptable", the UN said Friday.

"The access we have in northern Rakhine state is unacceptable", the head of the United Nations humanitarian office, Mark Lowcock, told reporters in Geneva, adding that he believed a "a high level" UN team would be able to visit the area "in the next few days".