BP PLC (BP) will withdraw from exploration blocks 5.2 and 5.3 offshore of Vietnam, a company official said Friday.

"This decision was made on the company's business consideration," said the official, who declined to be named.

"BP Vietnam is in discussions with PetroVietnam and partners to progress the withdrawal during 2009," she added, without giving an exact time frame for the withdrawal.

BP and PetroVietnam and ConocoPhillips have been jointly exploring oil and natural gas reserves since before 2000, said a PetroVietnam official in Hanoi.

In Block 5.2, BP holds a 55.9% stake, PetroVietnam 24.1% and ConocoPhillips 20.0%, while in Block 5.3, BP has a 60% stake, and PetroVietnam and ConocoPhillips each have a 20% stake, PetroVietnam figures showed.

"The parties involved in the two blocks are discussing the withdrawal," he noted, giving no further details.

BP is the biggest foreign producer of natural gas in Vietnam, with its operations supplying 3 billion cubic meters of natural gas a year from Block 06.1 in the Nam Con Son Basin.

BP's natural gas is supplied to the Phu My gas-fired power plant in Ba Ria Vung Tau, which accounts for more than 30% of the electricity produced in Vietnam, BP figures showed.

According to Hanoi-based financial analyst Bui Kien Thanh, BP's decision to leave the areas will hurt Vietnam's efforts to raise its natural gas supply to boost power production.

"As the two blocks are located at areas of difficult conditions for production which will certainly need the participation of strong international players, without BP, Vietnam will have to delay its plans to bring gas onshore," Thanh said.

He added that it's not clear whether BP would abandon its investment in the areas completely.

-By Nguyen Pham Muoi, Dow Jones Newswires, 84-913-220-614; phammuoi.nguyen@dowjones.com