Human Rights Watch said the workers routinely have their wages confiscated in the form of recruitment fees and have their passports taken away, making it difficult for them to leave abusive employers in the construction and domestic servant industries.
Migrant workers, predominantly South Asian in origin, make up 77 percent of the workforce in Bahrain, Human Rights Watch said, and are routinely discriminated against in Bahraini society.
While government reforms such as a ban on midday outdoor construction during dangerously hot summer months, have helped the situation, greater enforcement is still needed, the group said in a 123-page report published Sunday.
"Bahraini authorities understand that migrant workers have helped build the country and have instituted some important reforms," said Joe Stork, deputy Middle East and North Africa director at Human Rights Watch. "But without more vigorous enforcement, these reforms do little to address the most widespread rights violations such as failure to pay wages and withholding workers' passports."
The group's report says government officials are lax in their enforcement of anti-human trafficking laws and suspect employers routinely get away with a slap on the wrist or no penalty at all for abusing workers.
Notable deaths of 2014 [PHOTOS]