The Human Rights Watch report documented 43 women who have been sexually abused by officials meant to protect them.
Nigerian soldiers and police raped and abused women and girls that fled violence by Boko Haram insurgents and are now residing in displacement camps, Human Rights Watch (HRW) said on Monday.
Women and girls fleeing Boko Haram's seven-year-old armed campaign are taking refuge in seven camps in Maiduguri, the capital of Borno State in Nigeria. The militant group, who is against the education of women, have abducted, raped and forced them into marriage, regardless of their age.
"It is bad enough that these women and girls are not getting much-needed support for the horrific trauma they suffered at the hands of Boko Haram," Mausi Segun, a senior Nigeria researcher at Human Rights Watch said.
Four people told HRW they were drugged and raped. Thirty-seven said they had been coerced into sex through false marriage promises and material and financial assistance.
"It is disgraceful and outrageous that people who should protect these women and girls are attacking and abusing them," Segun continued.
The watchdog said the government is not going after abusers that include "camp leaders, vigilante groups, policemen, and soldiers."
Nigeria's President Muhammadu Buhari has ordered an investigation into the allegations.
A 17-year-old girl said she was raped by a policeman who approached her in a camp.
"One day he demanded to have sex with me. I refused but he forced me," she said, adding that it happened once. She said he threatened to shoot and kill her when she discovered that she was pregnant.
Another girl - a 16-year-old who fled an attack on Baga, near Lake Chad, last year - said she was drugged and raped in May 2015 by a community security group member in charge of distributing aid in the camp.
Dire conditions give way to abuse
The report says the lack of basic necessities in camps makes women and girls more vulnerable to being sexually exploited and raped by the camp officials. In some of the camps, their movement is severely restricted.
In other cases, officials are alleged to have used their positions of authority and promised women gifts of desperately needed food or other items in exchange for sex.
Another woman said she consented to have sex with a soldier because she needed help in feeding her four children. She said they only got one meal a day. The soldier, who proposed marriage to her, disappeared when she told him she was pregnant.
"Failure to respond to these widely reported abuses amounts to severe negligence or worse by Nigerian authorities," Segun said.
"Authorities should provide adequate aid in the camps, ensure freedom of movement for all displaced people, safe and confidential health care for survivors, and punish the abusers."
Boko Haram, which is literally translated to "Western education is forbidden," say they are against ‘westernisation' of Nigeria.
They have displaced more than two million people and killed some 15,000 in the country's northeast.
In April 2014, the group kidnapped nearly 276 schoolgirls from the Chibok town of the Borno state to prevent their education.