Chinese President Xi Jinping's family features in the explosive revelations made by the leak of confidential documents showing how world's most rich and prominent people hide their wealth.

Xi's brother-in-law Deng Jiagui and family members of at least eight current and former members of China's powerful Politburo Standing Committee have set up offshore companies through Mossack Fonseca, the Panama-based law firm that has offices in more than 35 countries.

The disclosures are part of the unprecedented leak of classified data, blowing the lid on how the murky world of shell companies operate, concealing their original identity. The 2.6 terabyte of data yielded up to 11.5 million documents from around 214,000 offshore entities. The probe was led by the International Consortium of Investigative Journalists (ICIJ) and German daily Sueddeutsche Zeitung.

Assets reportedly belonging to around 140 political figures from across the globe figured in the leaks. Other prominent figures include Russian President Vladimir Putin, king of Saudi Arabia, prime ministers of Iceland and Pakistan.

The ICIJ reported that the documents reveal Xi's brother-in-law had set up two British Virgin island companies in 2009. Representatives of Xi, who has mounted a high-profile corruption crackdown domestically in recent years, have not yet responded to the disclosures.

Former Chinese premier Li Peng's daughter Li Xiaolin and a grandchild of Jia Qinglin, a top-ranking Chinese Communist official, have also been identified in the leaks.

An investigation into the vast trove of documents was undertaken by more than 100 media groups. Although many of the operations could be deemed legal, which has been admitted by the ICIJ itself, the potential tax-evasion dealings are bound to have serious political ramifications across continents.

"I think the leak will prove to be probably the biggest blow the offshore world has ever taken because of the extent of the documents," said ICIJ director Gerard Ryle.

In another high-profile dealing, Putin's close associates are thought to have funnelled "as much as $2bn through banks and shadow companies", the ICIJ said. Nevertheless, Putin's name itself does not appear in any of the dealings.

The German daily Sueddeutsche Zeitung has said the exposé provides "rare insights into the world that can only exist in the shadows".