The organisation said the report was prepared after two months spent studying 13 garment factories and interviewing workers.
Female workers in many of the factories alleged beatings were frequent and managers cheated on salaries, which are paid on a piece rate. "New managers state explicitly that they prefer to hire inexperienced, young girls from the provinces because they are easier to control." the report said.
"There is no official minimum wage in Cambodia. There are no trade unions and no right to bargain. Labour inspectors report they are often barred from entering factories." It said some employees make as little as $10 (pounds 6) a month.
"There are effectively no occupational health and safety standards, since the relevant articles under the old State of Cambodia law have no provisions for enforcement." the report said.
Women at one factory "referred to the manager as 'Pol Pot'," the report said, in reference to the leader of the 1975-79 Khmer Rouge regime, blamed for the deaths of about 1 million Cambodians.