Workers in Asia who assemble parts for several leading mobile phone companies suffer under poor working conditions that include being punished for mistakes, Swedish rights agencies said in a report said Wednesday.

Workers in plants in China and the Philippines have to work long hours, sometimes 10-12 hours a day to make ends meet, according to the report compiled jointly by the non-governmental Fair Trade Centre organization, the watchdog Swedwatch, and Church of Sweden Aid.

The workers are punished for mistakes they make when exhausted, according to the report titled Silenced to Deliver: Mobile phone manufacturing in China and the Philippines.

"Young women pay a high price for the mobile phones we use and they have few ways of influencing their situation since independent trade unions are often banned at the plants," Swedwatch researcher Sara Nordbrand said.

The report focused on the working conditions at plants that supply components to mobile phone makers, including Nokia, Samsung, Motorola, LG, Sony Ericsson and Apple iPhone.

Annika Torstensson of Fair Trade Centre said the mobile phone companies could help improve conditions by enforcing their codes of conduct and spot checks but "permanent change will only come about when employees are allowed to unionize and freely express their views."

The report suggested that many of the assembly plant workers are women aged 16 to 30.

China accounts for about half of the global production of mobile phones. Factories worldwide churn out an estimated 36 mobile phones per second, the report said.