Lurid reports of Chinese officials sporting luxury watches or promoting their twin mistresses are being hailed by state media as proof of a corruption crackdown -- but real reforms remain a distant prospect.

Less than a month after Xi Jinping ascended to China's most powerful post as head of the Communist Party and proclaimed the scourge of graft an existential threat to the ruling organisation and the country, official outlets are striving to show action is being taken.

Several senior Chinese officials have been placed under investigation, including the vice party head of Sichuan province and a former deputy mayor of the manufacturing hub of Shenzhen.

A web page run by the Communist party's official newspaper, the People's Daily, hailed their fall as "the start of an anti-corruption storm".

But the breadth and depth of the campaign are still unclear, even as corruption threatens the ruling party's claim to legitimacy -- a recent Pew Research Center survey found 50 percent of Chinese considered official graft a very big problem.

Since Xi's promotion after the Communist Party Congress, a motley parade of lower-level officials have been featured by state-run media after being exposed, including a police chief being investigated for allegedly keeping twins as mistresses and giving one a local government job.

The mayor of Lanzhou, the capital of Gansu province, was pictured apparently wearing a range of expensive watches, and an official in the southwestern metropolis of Chongqing was sacked after a video of him having sex with a mistress spread like wildfire.

A Chinese investigative reporter on Thursday used Sina Weibo -- a website similar to Twitter -- to accuse the head of China's National Energy Administration of fraud, graft and sending death threats.

The official, Liu Tienan, was travelling in Russia with Wang Qishan, China's newly appointed anti-corruption chief, the state-run Global Times reported, making the accusations potentially embarrassing for the senior official.

The energy body quickly moved to dismiss the report, but the original post on Sina Weibo was not deleted by censors on Friday, as often happens with items critical of high-level officials.

The state-run Global Times gushed over the post, saying there had been a "surge" in online whistleblowing since Xi's installation, with 17 officials reported by "mistresses, journalists, web users and inside sources".

But despite the reports' prominence the figure amounts to a minuscule fraction of the Communist Party's 82 million strong membership.

Xi has been widely expected to order a new crackdown on corruption following a traumatic year for the party that included the downfall of top official Bo Xilai, now facing criminal trial for bribery.

Corruption investigations against party members are dealt with internally, raising allegations that they are used as tools in factional infighting.

Failed attempts by Ling Jihua, a close ally of President Hu Jintao, to cover up the death of his son in a Ferrari accident in March reportedly played a key role in the pre-congress manoeuvring.

Li Chuncheng, the Sichuan vice party head, was promoted during Hu's reign as party chief, and the probe "looks like it's politically motivated", said Jean-Pierre Cabestan, a professor at Hong Kong Baptist University.

"There is a link with the weakening of the Hu Jintao faction."

China has no laws compelling officials to declare their assets publicly, and there is widespread suspicion that regulations forbidding party officials from engaging in business activities are routinely flouted.

"The whole system is opaque, there's no way to check," Cabestan said.

While some senior Chinese officials have said that office-holders will be forced to declare their assets in future, no timetable for such reforms has been announced.

Significant changes are unlikely any time soon as they would threaten the party's influence, said Cabestan.

"There is opacity in the whole system which will remain unchanged unless there is potentially destabilising political reform," he said.

Control over the media by the party, which can use its powers to scotch corruption exposes, also hampers anti-corruption efforts.

In the meantime there is increasing scepticism of anti-corruption drives among the Chinese public, said Joseph Cheng, a political analyst at the City University of Hong Kong.

"If you simply rely on a campaign of crackdown on so-called big cats at the deputy level, this attracts a bit of publicity, but we all know this is not going to solve the problem," he said.

"Ordinary people have seen too many crackdowns already."