Foxconn, which manufactures and assembles Apple’s iphone, suspended its production in China on Monday after 2,000 employees rioted, injuring 40 people.
The fight took place at a privately managed dormitory near a Foxconn Technology Group factory in the northern city of Taiyuan.
According to the company the incident escalated from what it called a personal dispute between several employees late at night.
Comments posted online on Chinese blogs stated that the fight may have been started by security guards who nearly beat a worker to death.
The windows of at least three gates' guard posts had been smashed with piles of glass littering the ground around them, reports Reuters.
Close to 5,000 officers were sent to restore order.
Foxconn said "the cause of this dispute is under investigation by local authorities and we are working closely with them in this process, but it appears not to have been work-related."
The Taiyuan plant, which employs about 79,000 workers, is owned by the world's largest contract maker of electronic goods.
The factory could be closed for up to three days.