China's Communist authorities are touting a suspended death sentence for an ex-minister as proof new leaders are serious about their avowed corruption crackdown, but analysts remain sceptical in the absence of systematic reforms.

Former rail minister Liu Zhijun on Monday became the highest-ranking official punished for corruption since the new leadership under President Xi Jinping vowed to clean up the ruling party.

He was convicted of bribery involving at least 64.6 million yuan ($10.5 million) -- but the scandal reportedly involved more than 10 times that amount.

In China suspended death sentences are routinely commuted to life in prison. Senior figures like Liu -- once hailed as the "father" of the country's high-speed rail network -- are often said to enjoy cushy prison conditions or medical parole.

Seriously tackling corruption would require fundamental reform, say analysts -- a daunting task given the powerful vested interests that would be disturbed, and leaders' overriding fear that destabilising the party could weaken its grip on power.

"People are looking for genuine systemic changes, genuine checks and balances, mechanisms being built, instead of just another campaign (where) everybody will lie low for a while," said Joseph Cheng, a Chinese politics expert at City University of Hong Kong.

Official corruption is often a factor behind the disputes that trigger public protests in China, where the leadership prioritises social stability and has sought to portray itself as committed to fighting graft.

The anti-corruption rhetoric of recent months has been unrelenting and full-throated, with Xi warning it could "destroy the party" and threatening "no leniency" for those mired in graft.

Several other senior figures have come under investigation, including major economic policy maker Liu Tienan, former deputy director of the National Development and Reform Commission, and top provincial officials.

Numerous low-level cadres have been sacked after Internet users exposed alleged -- sometimes salacious -- scandals, some involving luxury watches or multiple mistresses.

Liu's sentence on Monday was trumpeted as further proof of intent, with the Xinhua state news agency saying it underscored "top leaders' resolve to target both high-ranking 'tigers' and low-ranking 'flies' in its anticorruption efforts".

But in a country that executes thousands of people a year -- the exact number is a state secret -- many ordinary Chinese saw the opposite: different standards for the powerful.

"For officials as high-ranking as Liu Zhijun, everybody knows how luxurious their prisons are... and these kinds of special privileges show once again how unfair the system is," wrote one user of the Twitter-like microblog Sina Weibo, under the handle Shiyang Pinglun.

Reports have described a prison outside Beijing, Qincheng, as reserved for elite inmates, offering more comfortable cells and relaxed treatment.

Another Weibo user, Laolao V, said: "This is like striking a tiger with a fly swatter."

Under Chinese law, capital punishment can be imposed for taking bribes exceeding 100,000 yuan, and the Beijing court found that Liu's offences deserved execution.

But it said it granted him leniency because he had confessed, shown repentance and helped investigators recover assets.

In high-profile cases like Liu's judicial sentences are routinely decided beforehand by political authorities, and the proceedings carefully handled. Conviction is a foregone conclusion and Liu's defence lawyers did not contest the charges.

Jean-Pierre Cabestan, a political scientist at Hong Kong Baptist University, said while Liu's treatment was "standard", the jury on the overall anti-graft campaign was still out, depending on whether more "tigers" were caught and how they were punished.

Among those expected to stand in the dock are Bo Xilai, former party chief of the southwestern megacity of Chongqing, for allegedly taking bribes and helping cover up his wife's murder of a British businessman.

"I think it's going to expand," Cabestan said.

But he cautioned: "How far, I don't know. We have to think about the fine line -- not to rock the boat, not to destabilise the system and create too much uncertainty."

The leadership's vehement promises have raised expectations of follow-through, even though the likelihood of that seems low, said Kerry Brown, a Chinese politics professor at the University of Sydney.

"They've put a huge amount of effort and rhetorical energy into it and it'd be very strange not have some kind of achievement," he said.

"My heart says it would be great if they do something systemic. And my mind says, nope, this is a political campaign."