Vinachem said it would invest returns from the sale into its core business, non-oil and fertiliser products.
The group currently owns 11 per cent of the complex's shares.
A representative of the National Oil and Gas Group (PetroVietnam)--which owns 18 per cent of the total capital at the complex--said after Vinachem withdrew its capital from the complex project, PetroVietnam would have the first chance to buy the group's shares. However, a Thai investor in the complex project was also ready to buy Vinachem's shares.
PetroVietnam, Vinachem, Vina SCG Chemicals Company and the Thailand Plastic and Chemicals Company Ltd signed a joint venture contract in March 2008 to develop the Long Son petrochemical complex.
The authorities of southern Ba Ria-Vung Tau Province granted an investment certificate to the project in July 2008.
The 400-ha complex will be built in the Long Son Industrial Zone near Long Son oil refinery with a total investment of US$4 billion and a total capacity of 3 million tonnes per year.
The complex is one of several projects the Viet Nam oil and gas industry has planned. The other projects include Dung Quat, Nghi Son and Long Son refineries. It is expected to produce an annual supply of 1.45 million tonnes of polyethylene (PE) and polypropylene (PP), 730,000 tonnes of chemical raw material for the production of polyvinyl chloride (PVC) and 840,000 tonnes of other kinds of chemical products for the petrochemical and chemical industry.
The complex is expected to meet 65 per cent of demand for PE and PP on the domestic market and to stabilise the raw material supply for the petrochemical industry.