Swedish fashion retailer Hennes & Mauritz (H&M) said it was collaborating with trade unions, the government as well as the U.N. to improve workers' conditions after a study found violations in supplying garment factories in India and Cambodia.

The study by the Asia Floor Wage Alliance (AFWA) found workers stitching clothes for H&M in factories in Delhi and Phnom Penh faced problems such as low wages, fixed-term contracts, forced overtime and loss of job if pregnant.

The AFWA, a coalition of trade unions and labour rights groups, accused the Western high street retailer of failing on its commitments to clean up its supply chain.

An official from H&M told the Thomson Reuters Foundation on Saturday the fashion firm has been working actively to improve the lives of textile workers for many years.

"The report raises important issues and we are dedicated to contribute to positive long-term development for the people working in the textile industry in our sourcing markets," said Thérèse Sundberg from H&M's press and communications department.

"The issues addressed in the report are industry wide problems. They are often difficult to address as an individual company and we firmly believe that collaboration is key."

H&M has partnered with the International Labour Organisation, the Swedish International Development Cooperation Agency as well as global and local trade unions to seek out solutions, she added in an emailed statement.

The fashion industry has come under increasing pressure to improve factory conditions and workers' rights, particularly after the collapse of the Rana Plaza complex in Bangladesh three years ago, when 1,136 garment workers were killed.

The study surveyed 50 Indian workers from five factories and 201 Cambodians workers from 12 factories from August to October 2015.

It found that overtime in all the factories was expected by employers. Cambodian workers reported they had to do two hours of overtime daily, while Indian workers reported working at least nine hours to 17 hours a day.

"Workers are routinely required to work until 2 a.m. in order to meet production targets — and then to report to work at 9 a.m.," it said, referring to workers in Indian factories.

"The financial imperative of working overtime due to the persistence of minimum wage standards below living wage standards can be viewed as a form of economic coercion that leads to involuntary or forced overtime," it added.

The study also found that fixed-term contracts were being used in nine of the 12 Cambodian and all Indian factories surveyed.

These contracts facilitate arbitrary termination and deprive workers of job security, pension, health care, seniority benefits and gratuity, say activists.

Workers also reported discrimination in maternity benefits in both the Indian and Cambodian factories, said the study.

Cambodian workers from 11 of the 12 factories reported either witnessing or experiencing termination of employment during pregnancy, while Indians from all five factories said women were fired during their pregnancies, said the study.

"Permanent workers report being forced to take leave without pay for the period of their pregnancy," it said.

"Contract, piece rate and casual workers reported that although most of the time they are reinstated in their jobs after pregnancy, they receive completely new contracts that cause them to lose seniority."

H&M's Sundberg said solving all these issues was a long-term process which continues "step by step" and that the Swedish retailer was committed to improving labour rights in its supplying factories.

"The continued presence of long-term, responsible buyers is vital to the future development of countries such as Cambodia and India, and we want to continue to contribute to increased improvements in these markets," said Sundberg.