Only medical vehicles and those delivering essentials are allowed on the streets.
The district’s more than 600,000 residents will have to take nucleic acid tests every day, the local government said, warning that it would “resolutely crack down on all kinds of violations”.
Foxconn told AFP on Wednesday its Zhengzhou park will “maintain closed-loop operations”, without providing details.
The company said at the weekend it was testing employees daily and keeping them in the “closed loop”, as well as offering transport to those who wanted to leave, after the videos on social media showed employees walking down motorways with their suitcases.
Local governments in the area surrounding Zhengzhou city have asked Foxconn workers to register with authorities if they return home and to complete several days of quarantine upon arrival.
The company also said on Tuesday it would quadruple bonuses for employees willing to remain at the factory during the outbreak.
Chinese social media users accused Zhengzhou authorities on Wednesday of “performatively” lifting COVID-19 restrictions after the city announced a day earlier it would “restore normal production and life”.
“In the morning, you lift the lockdown, then at night, you lock down again, what are you trying to do?” Weibo user Taodixing asked.
China reported more than 2,000 fresh domestic infections on Wednesday for the third day in a row.
Henan province, where Zhengzhou is located, officially reported 359 COVID-19 infections on Wednesday, a jump from Tuesday’s 104.
The southern Chinese manufacturing hub of Guangzhou also announced partial lockdowns in several districts this week in response to rising case numbers.