China posted a record number of daily Covid cases on Wednesday, amid a surge in the Omicron strain.
It stepped up lockdowns in affected areas such as Zhengzhou, home to the world's largest iPhone plant.
The IMF called on China to recalibrate its Covid-zero stance, to support the economy.
Zhengzhou, a city in east-central China and home to the world's largest Apple iPhone factory, will largely be locked down from Friday until next Tuesday, local authorities said late on Wednesday.
The restrictions come amid a surge of COVID-19 infections in China. Officials in Zhengzhou are calling the situation - which is mainly concentrated in the urban regions - "still severe and complicated."
China is experiencing a severe outbreak of the highly transmissible Omicron variant, mounting a challenge to the country's draconian Covid-zero stance. China reported a record high 31,444 local infections for Wednesday, including asymptomatic cases, according to the country's National Health Commission.
The relentless drive to stamp out Covid is driving discontent in the country - including at Apple's largest iPhone-making factory in Zhengzhou, where workers were reportedly rioting against pandemic restrictions on Wednesday.
The surge in COVID-19 cases is also casting doubts on whether the world's second-largest economy will be able to completely exit the pandemic.
Earlier this month, the Chinese stock markets rallied on speculation that the country was preparing to loosen its Covid-zero stance. But that optimism now appears to be misguided, because there are not enough hospital intensive care unit, or ICU, beds for a widespread outbreak in China, Bloomberg Intelligence said on Wednesday.
"There's no way an uncontrolled wave of infections can be managed" Bloomberg Intelligence senior pharmaceutical analyst Sam Fazeli in the report. "This reinforces the need for local infection control, including closing of businesses, prolonging China's reopening."
He estimates a full reopening of China's economy is likely to stretch beyond 2023.
Even the International Monetary Fund called on China to adjust its COVID-19 strategy in order to support the economy.
"Going forward, a further recalibration of the COVID strategy should be well prepared and include boosting the pace of vaccinations and maintaining it at a high level to ensure that protection is preserved," said First Deputy Managing Director Gita Gopinath in a statement.
Despite the surge in COVID-19 infections in China, the Chinese and Hong Kong markets are flat at midday on Thursday.