Refined fuel stocks, however, fell 1.25 percent at end-September from a month earlier, the newsletter Xinhua OGP said.
Among refined fuels, gasoline inventory rose 1.63 percent from end-August, kerosene stocks soared 10.3 percent, and diesel stocks fell 5.52 percent, OGP said.
The newsletter does not provide outright inventory volumes.
The government rarely discloses levels of either commercial or strategic oil stocks, making it difficult to gauge real demand in the world's second-largest oil consumer.
Implied oil demand in China, the world's second-largest oil consumer, posted its first yearly decline in 17 months in September as refiners cut crude runs to perform maintenance. But real demand may have been stronger than the implied figure, which ignores changes in fuel stocks.