The complex, in east China's Zhoushan city, is now producing oil products and chemicals to commercial specifications, Zhejiang Petrochemical said on its website.

The company, 51% owned by private chemical group Zhejiang Rongsheng Holdings, said it has started test production at ethylene, aromatics and other downstream facilities, without giving further details.

Zhejiang Petrochemical started a first 200,000 barrels per day (bpd) crude processing unit in late May, following on from the start of a 400,000-bpd refinery owned by another private chemical major Hengli Petrochemical.

The newly started units at Zhejiang Petrochemical should include a second 200,000-bpd crude unit, a 1.2 million tonnes per year (tpy) ethylene unit and a 2 million tpy paraxylene unit, according to several industry sources with knowledge of the plant's operations.

(Reporting by Chen Aizhu; Editing by Richard Pullin)