Productions of Apple's iPhone 5 may have been dented as thousands of Chinese factory workers went on strike over working a national holiday.

The protests, involving around 4,000 workers, reportedly left many iPhone 5 production lines "in a state of paralysis for the entire day" as pressure increases to meet customer demand.

But despite the reports, Foxconn, a leading Apple manufacturer, denied any factory unrest even though workers were required to work through China's Golden Week holiday, from October 1-8.

The alleged strike comes two weeks after 2,000 Chinese workers rioted in a Foxconn factory, leaving 40 injured.

The mass brawl at the plant caused the supplier to close business after police were called to break up fighting between factory employees.

But again the company denied Apple production was affected, in the midst of a worldwide demand for the latest smartphone release.

Foxconn has required staff to work overtime during this period to meet the demands with this believed to have triggered arguments between quality control inspectors and factory workers according to New York-based China Labor Watch (CLW).

"Foxconn raised overly strict demands on product quality without providing worker training for the corresponding skills," CLW says.

"This combination of factors led to the strike."

But Foxconn, who paid staff triple pay during the period, denied any disturbance to production.