Beijing: In the middle of the biggest anti-corruption campaign for years, crooked Chinese politicians are paying to vanish from sight, with all negative stories about them scrubbed from the internet.

"It does not matter how big or sensitive the story is, we can make it disappear," promised a manager at Yage Times, China's largest and most notorious "black" public relations firm.

Dozens of Chinese officials have been put under investigation in recent months, and Communist Party members at every level are worried. In particular, they fear the internet, where stories about corrupt officials often go viral, putting pressure on the Communist Party to launch a high-profile investigation.

In almost 42 per cent of this year's corruption cases, the public has provided a tip-off, often on the web, according to Zhang Shaolong, an official at the party's discipline unit.

As a result, the market for "black PR" is booming. A quick search showed at least 30 companies have sprung up to offer government officials, shady businessmen and scandal-hit celebrities the chance to wipe their slates clean.