Apple said Covid restrictions have "temporarily impacted" production at the world's largest iPhone factory in central China, warning that customers will now face longer wait times ahead of the holiday season.

Foxconn, Apple's principal subcontractor, locked down its massive factory in Zhengzhou last month after a spike in infections – in line with wider pandemic restrictions in the city.

"Covid-19 restrictions have temporarily impacted the primary iPhone 14 Pro and iPhone 14 Pro Max assembly facility located in Zhengzhou, China," California-based Apple said in a statement late on Sunday.

"The facility is currently operating at significantly reduced capacity."

Despite strong demand for Apple's products ahead of the holiday season, "we now expect lower iPhone 14 Pro and iPhone 14 Pro Max shipments than we previously anticipated", it said.

"Customers will experience longer wait times to receive their new products."

Foxconn is China's biggest private sector employer, with over a million people working across the country in about 30 factories and research institutes.

But Zhengzhou is the firm's crown jewel, churning out iPhones in quantities not seen anywhere else.

Local authorities locked down the area surrounding the factory on Wednesday, while health officials reaffirmed the nation’s Covid strategy.

National Health Commission spokesperson Mi Feng on Saturday said that Beijing would "stick unswervingly to... the overall policy of dynamic zero-Covid".

"At present, China is still facing the dual threat of imported infections and the spread of domestic outbreaks," Mi said at a press briefing.

"The disease control situation is as grim and complex as ever," he said. "We must continue to put people and lives first." (AFP)