'Violating human rights'
Up to 300,000 Rohingyas, who have been described by the United Nations as one of the most persecuted minorities in the world, have fled across the border to Bangladesh since the 1970's.
The report said the country's authorities were waging a campaign of "arbitrary arrest, illegal expulsion, and forced internment".
The police are "systematically rounding up, jailing or summarily expelling these unregistered refugees across the Myanmar border in flagrant violation of the country's human rights obligations," it said.
'Baseless and malicious'
The report follows two other reports: one by Arakan Project, a lobby group, and another by Doctors Without Borders, a humanitarian NGO, which also criticised the crackdown.
The Bangladeshi government has dismissed the accusations as "baseless and malicious".
It views the Rohingya as illigal immigrants and maintains they must be repatriated.
"We are arresting illegal Rohingya and pushing them back over the border. It is an ongoing operation," said Rafiqul Islam, a Bangladeshi police chief.