Russian President Vladimir Putin's inner circle shuffled as much as $US2 billion ($2.7 billion) through shadow companies using a network of law firms and banks that helps billionaires, celebrities, politicians, fraudsters and drug traffickers hide their wealth, confidential documents show.

One of the biggest leaks of confidential financial information in history, obtained in a global investigation by media organisations including The Australian Financial Review, reveals the inside workings of a shadowy financial system that allows the wealthy and powerful to shift capital around the world where governments and tax agencies can't find it.