Formosa Plastics, Taiwan's largest diversified industrial group, plans to invest US$2.3 billion to expand its plant in Ningbo, Zhejiang Province, over the next two to three years.

The plan has passed the mainland's environmental impact assessment and is awaiting approval from the National Development and Reform Commission.

Its Ningbo plant currently produces 2.3 million tons of plastic material annually, including 600,000 tons of purified terephthalic acid, which is used to make plastic bottles and clothing. It sources its raw materials from both Taiwan and the mainland.

It was built for US$2.25 billion, 12.5 percent of which was spent on environmental pollution control, said assistant director Huang Chen-ching.

Formosa Plastics had combined sales of US$3.48 billion in October, an increase of more than 3 percent over September's US$3.37 billion. It also has production bases in Vietnam and the U.S.