Despite dominating the international news agenda, the explosive findings garnered scarce coverage on the mainland and was left untouched by the party's main state-run news outlets on Monday. Reports on wealth linked to Chinese President Xi Jinping in Beijing had already been published. Credit:AP Several popular commercial news portals ran stories which focused on Mr Putin and excised any mention of links to Chinese officials. But these too were deemed too politically sensitive and were scrubbed from the Chinese internet by Monday evening; with defunct article links redirecting to the sites' homepages. Google, Facebook and Twitter are blocked in mainland China, along with a host of major western news outlets. Searches for the term "Panama Papers" on major Chinese search engines like Baidu returned heavily filtered results accompanied with a customary notice displayed whenever a search deemed too sensitive or subversive is made: "According to relevant laws and regulations, some of the search results are not shown". The news, which broke early on Monday morning local time, took several hours to jump the language barrier. But as discussion on Chinese social media began to gather momentum, hundreds of offending posts were soon deleted and a topic page for the Panama Papers hashtag was censored. Searches for key terms and names linked to Chinese politicians were also blocked.

While there are legitimate uses for shell companies registered in offshore tax havens, any insinuation of impropriety within Mr Xi's extended family could prove toxic given he has waged a far-reaching anti-corruption campaign to restore his party's credibility in the eyes of a Chinese public fed up with endemic graft. Discussion of the wealth of the party elite and their relatives is regarded as strictly off-limits by the Chinese leadership. Censored search for Panama Papers on Baidu. Credit:Philip Wen In 2012, separate investigations by Bloomberg and the New York Times revealing the wealth and business dealings of the families of Mr Xi and then Premier Wen Jiabao prompted Beijing to retaliate by blocking the news sites in China, as well as the denial of journalist visas for several years. Under Mr Xi's leadership, China has sought to tighten the reins on its self-described "internet sovereignty" even further and mainland journalists have come under increasing pressure to toe the party line, particularly as the party leadership struggles to steer the country's slowing economy through a difficult transition. Russian President Vladimir Putin's associates made an appearance in Panama Papers. Credit:AP

As well as the president's brother-in-law, Deng Jiagui, among the high-profile names listed in the year-long investigation led by Suddeutsche Zeitung and the International Consortium of Investigative Journalists is Li Xiaolin, the energy tycoon daughter of former Premier Li Peng. The document dump revealed Ms Li held a Hong Kong passport, which became a talking point – albeit an abortive one – on Chinese social media. Both Mr Deng and Ms Li had been previously named in another major investigation coordinated by the ICIJ published in January 2014, detailing the "secretive offshore companies in tax haves that helped shroud the Communist elite's wealth". That investigation was notable for the involvement of Hong Kong newspaper Ming Pao, as well as journalists from a prominent Chinese publication who pulled out after being warned by the Chinese government. In February 2014, Ming Pao's chief editor Kevin Lau was stabbed repeatedly in a brutal attack, prompting ICIJ director Gerard Ryle to condemn the attack. Police later said the assailants, some who had triad connections, were likely "hired hands". "While many have speculated about the motives behind the attack, we are not aware of any evidence linking the violence to Ming Pao's reporting partnership with ICIJ on the Offshore Leaks investigation," Ryle, a former Sydney Morning Herald reporter, said at the time. "Such speculation, however, does reflect the real concern and anxiety felt by many in the Hong Kong press corps over continuing threats to press freedom." The chilling effect on the freedom of the press by growing mainland influence on the city has been exacerbated by the disappearance of five Hong Kong booksellers who specialised in the publication of literature critical of the Communist Party.

Neither Ming Pao nor any other mainstream Hong Kong news outlet were named among ICIJ's more than 100 reporting partners worldwide for the Panama Papers investigation. It proved a busy Monday for Chinese internet censors. According to Free Weibo, which monitors deleted posts on the social media platform, the Panama Papers was only the second most censored topic. It came behind news of the top winner at Hong Kong's annual film awards. The prize for best film went to Ten Years, a dystopian portrayal of a Hong Kong completely taken over by mainland China, set a decade into the future. Follow FairfaxForeign on Twitter Follow Fairfax Foreign on Facebook