A 25-year-old Sri Lankan had been rescued after allegedly being held against her will by her sponsor for almost 18 months, Bahrain Daily News reported.
Velusundaram Manjula arrived in the country in 2009 to work as a housemaid for a Bahraini family.
Activists say she was promised a salary of BD85 a month, but got only BD60 when she arrived. She was also forced to work around 21 hours a day in two separate households.
Ms Manjula reportedly went to the police after two years, but was allegedly ignored.
A year later, she approached them again. But as she was not a victim of abuse, she was referred to the Labour Ministry.
Ms Manjula later took refuge at the MWPS shelter, where she has been staying for more than a month.
From left, Ms Manjula, Ms Szalay and MWPS chairwoman Marietta Dias at the Press conference
MWPS action committee head Liz Szalay said it was common for workers not to be paid the salary promised to them before they arrive in Bahrain.
"It is a problem here and it is blatant," she said during a Press conference at the society in Adliya yesterday.
"You see advertisements for BD60 posted up but there is no Sri Lankan consular or embassy here.
"Because there is no representative here, workers and especially Sri Lankans and Ethiopians are taken advantage of."
Ms Manjula, who has a seven-year-old son, has filed a police complaint against her sponsor claiming she was held under duress.
However, the MWPS say she is set to return home penniless after lengthy negotiations with her sponsor about her severance pay broke down.
The organisation will also have to fund her air ticket.
"She signed her contract in Sri Lanka at the Sri Lankan Bureau of Foreign Employment that she would be receiving BD85 but she got just BD60," said Ms Szalay.
"She worked in two houses at the same time - the daughter's house and the mother's.
"She worked 22 hours a day for only BD60 and still had to buy her own shampoo, soap, uniform, food and even her bed sheet."
Many low-income workers opt to go home rather than wait for justice as they are unable to work until a verdict is issued and cannot afford to stop earning money to feed their families.
Activists say while the police, Labour Ministry and General Directorate of Nationality Passports and Residency (GDNPR) acknowledge the problem, a lack of communication is hampering efforts to prosecute those responsible.
"The cases take such a long time to come to court," said Migrant Workers Protection Society (MWPS) general-secretary Beverley Hamadeh.
"Regrettably, sometimes we tell our clients to go home because it will be too expensive as they can't work or switch sponsors while things are in court."