The facility in southern Vietnam, a key iPhone camera module manufacturing facility in the country, has gradually resumed production in recent days, an executive familiar with the situation told Nikkei.

The delay in making the new sensor-shift optical image stabilization module is causing buyers of iPhone 13 face longer delivery times, it said.

"There's nothing we can do but to monitor the situation in Vietnam every day and wait for them to ramp up the output," one of the executives with direct knowledge told the news outlet.

The module is used on all four new iPhone 13 models. Previously, it was only in the premium iPhone 12 Pro Max.

Vietnam has suffered severe Covid-19 impacts in the fourth wave, resulting in strict restrictions being imposed on factories and transportation in many localities, especially in HCMC and neighboring Binh Duong Province.