China is dismissing a report by a global corruption monitoring group that said graft is worsening in the past year, despite Beijing's intense focus on the issue.
China fell 20 places to 100th in the world in Transparency International's annual Corruption Perceptions Index released Wednesday.
It is a potential embarrassment for the Communist Party, which has launched a highly publicized crackdown on corruption since President Xi Jinping came to power in late 2012.
Corruption Perceptions Index 2014
Foreign Ministry spokeswoman Hua Chunying on Wednesday cast doubt on the findings, saying the group should "examine the objectiveness and neutrality" of its work.
"It is well known to the world the Chinese government is resolute in cracking down on corruption, and the achievements made by us in the corruption campaign are well known to the world," Hua said.
"He index score and ranking of China in the 2014 Corruption Perceptions Index is seriously inconsistent with the achievements made by China in the anti-corruption campaign," she said.
China scored just 36 out of a possible 100 points in Transparency International's index. That is down from the 40 points it scored in 2013.
The report acknowledged many Chinese officials have been convicted of corruption but said too many of these cases have been held "behind closed doors."
A large number of low-level officials and even some high-ranking Communist Party members have been brought down in the crackdown.
But it is unclear if the anti-graft campaign can succeed, since it does not appear to be working alongside any wider reforms of China's political system.
In addition, the country's courts are controlled by the Communist Party, making it difficult to judge whether corruption convictions have political motives.