China's biggest offshore oil producer CNOOC Ltd said talks are still ongoing for a $7 billion bid to buy BP Plc's stake in Argentina-based oil and gas group Pan American Energy LLC (PAE), despite a lapsed deadline on Tuesday.

On October 25, CNOOC said Bridas Corp, its 50 percent joint venture, had not obtained the necessary regulatory approvals to complete the bid, without giving further information. It had said Nov 1 was the deadline after which either party would have the right to terminate the agreement.

"Regarding the Pan American transaction, related parties are continuing discussions. If there are new developments, we will send out a public statement," a CNOOC spokeswoman told Reuters on Tuesday.