Many online critics did not buy the explanation, saying that such expensive liquor could not be sold out of gas station convenience stores.

"No wonder we pay sky-high prices for gas. We have to do so the company can drink Moutai," said a netizen nicknamed Qunzhong.

But Cao Lin, a commentator for the Shandong-based web portal Dzwww.com, said further investigation made him wonder if it was possible that the bottles could be sold out of gas stations after all.

"I went to some of Sinopec's convenience stores and was surprised to find many things there that I was not expecting -- Martell XO, non-vintage Moutai and some high-end electric appliances," Cao said.

He suggested that some people whose fuel bills are paid with public money were using the privilege to buy other things.

Earlier media reports said Sinopec Guangdong's turnover from non-petrol business in 2010 amounted to nearly 700 million yuan, of which 25 million yuan came from liquor sales.

The scandal has not been the first for Sinopec. In July 2009, online posts claimed the corporation had splashed out 12 million yuan on hanging lamps for its headquarters. The corporation said later that it had actually paid about 1.6 million for the hanging lights.