State oil monopoly Petrovietnam said on Monday it had extended by two months the bidding for exploration licences in nine offshore oil blocks. Officials from Petrovietnam said the extension to early May was to attract more bids for the deep water blocks in Phu Khanh basin off Vietnam's central coast. Vietnam, Southeast Asia's third largest crude producer after Malaysia and Opec-member Indonesia, has stepped up oil exploration to reverse a decline in oil output.
It was unclear how many of the 30 foreign oil firms invited to take part in the licensing round, launched in September last year, had submitted bids.
Petrovietnam said last year preliminary studies showed the basin, close to Vietnam's two biggest producing fields, Bach Ho and Su Tu Den, held probable oil and gas reserves of 1.5 billion barrels of oil equivalent.
The licences offer production sharing contracts on any discoveries for 30 years, extendable a further five years.
Petrovietnam said it would limit its participation in the blocks to 20 percent.
Phu Khanh Basin is a deepwater basin located along the southern central coastline of Vietnam with water depths from 50 metres to 2,500 metres and thick sediment of up to 8,000 metres.
The nine blocks cover an average 7,000 sq km (2,700 sq mile) per block.