Health authorities found the wife of a previously confirmed Covid-19 patient was employed at the Taiwanese-invested company that employs 65,000 staff in Binh Tan District.
Samples are currently being collected from all 1,100 employees from the same section as the woman before all self-isolate at home, with the entire premises to be disinfected, said Kim Vinh Cuong, deputy head of the company labor union.
Other sections of the company, the largest employer in the city, remain operational.
Last year, the company had to halt operations for two days in April to protect employees from the novel coronavirus.
Vietnam has recorded over 6,300 new local cases in the latest Covid-19 wave, with 481 of them in HCMC.