The $1 billion will double the company’s capacity when the new facility begins production in 2025, according to city authorities.
The company, which set up a plant in 2017 at a cost of $1 billion, reported revenues of VND78.2 trillion ($3.32 billion) and profits of VND2.5 trillion last year.
It employs around 3,500 workers.
The approval from authorities in the northern port city comes just after South Korean President Yoon Suk Yeol wrapped up a three-day official visit to Vietnam on Saturday with a delegation that also comprised LG Group chairman Koo Kwang-mo.
The $1 billion takes Hai Phong’s foreign direct investment in the first half of the year to $1.9 billion, or 95% of its full-year target.