China National Petroleum Corp reported one-third less profit in the third quarter from a year before, financial documents from China's largest oil and gas producer and supplier showed on Tuesday.

CNPC has recorded 551.6 billion yuan ($88.4 billion) in revenues by September this year, 3.95 percent more than the same period in 2011, but the 24.9 billion yuan profits in the third quarter have declined by 33.4 percent.

The poor performance in the third quarter extended the overall profit decrease in the first three quarters from 6 percent to nearly 16 percent.

Just two days before CNPC's report was released, another oil Giant, China Petrochemical Corp, also known as Sinopec, reported a net profit of 18.2 billion yuan in the third quarter, which slid 7.5 percent year-on-year.