China National Petroleum Corp, the country's biggest oil producer, is in talks with Ecuador's government over a potential investment in the OPEC member's $12.5 billion Pacifico refinery project, an Ecuadorian minister said.

Chinese oil companies have been buying overseas oil and gas assets to secure supply to the world's second-largest oil consumer and maximize returns on oil produced overseas.

The Pacifico refinery complex is a joint venture between state-run Petroecuador and Venezuela's state oil company PDVSA.