"The government’s eagerness to attract foreign investment led it to promote the lowest base wage in any garment-producing country - now set at the equivalent of $26 (£20) a month," researchers for the New York University Stern Center for Business and Human Rights found.

"On that amount... workers cannot afford decent housing, food or transportation."

Meanwhile Chinese garment workers earn $340 a month, according to AP news agency, and those in Kenya earn monthly pay of $207.

Research focused on the Hawassa Industrial Park which employs 25,000 workers.

H&M, Gap, Calvin Klein and Tommy Hilfiger are among the brands whose items are produced there.

The report authors recommend the introduction of a minimum wage and diversifying into higher-value clothing and other manufactured goods.