Around 1,000 workers at a factory in southern China that makes components for Apple and IBM have gone on strike.

The Associated Press reports that the industrial action was taken by workers objecting to long hours.

Workers walked out of the plant on Tuesday and blocked the main highway into the city of Shenzhen. Riot police were reportedly deployed to keep order.

China Labor Watch, a US-based organisation, said that it was not uncommon for staff to work 120 hours of overtime at the plant. Concerns about injuries, abuse and layoffs of older workers were also aired, AP reports.

The plant is owned by Taiwan's Jingyuan Computer Group, which supplies components including keyboards to Apple and IBM.

"China Labor Watch calls upon Apple, IBM and the other clients ofthis factory to assume responsibility for these workers’ dissatisfaction and work with the factory to improve the working conditions in the factory. We particularly urge Apple to take responsibility, as there are more than 300 workers working on the Apple keyboard assembly line," China Labor watch said in a statement.

The strike was ended after management agreed to reduce overtime requirements. Industrial action is relatively rare in China though 400 female workers at a bra factory, also in Shenzhen, downed tools earlier this week.