An industral park in Zhengzhou that hosts an iPhone factory belonging to Foxconn announced a fresh Covid-19 lockdown on Wednesday.

The Zhengzhou Airport Economy Zone in central China said it would impose "silent management" measures with immediate effect, including barring all residents from going out and only allowing approved vehicles on the roads. The curbs will stay in place until November 9, it said.

Foxconn, formally Hon Hai Precision Industry, is Apple's biggest iPhone maker, producing 70 percent of iPhone shipments globally. It makes most of the phones at the Zhengzhou plant where it employs about 200,000 people, though it has other smaller production sites in India and south China.

The industrial park's notice did not specify how the measures might be applied to Foxconn.

Wednesday's lockdown marks a re-tightening of measures in Zhengzhou, which lifted a quasi-lockdown on its nearly 13 million people the day before. (Reuters)