Foxconn has so far invested $1.5 billion in Vietnam and plans to raise its investment by $700 million and recruit 10,000 more local workers this year.
Separately, state media reported last week Foxconn was also looking into investing $1.3 billion in Thanh Hoa province, 160 km (99.42 miles) south of Hanoi.
Foxconn is moving some iPad and MacBook assembly to Vietnam from China at the request of Apple as the U.S. firm diversifies production to minimize the impact of Sino-U.S. trade tensions.