BERLIN — The release of a vast trove of documents and other data on offshore financial dealings of wealthy, famous and powerful people around the world is raising questions over the widespread use of such tactics to avoid taxes and skirt financial oversight.

Reports by an international coalition of media outlets on an investigation with the Washington-based International Consortium of Investigative Journalists brought to light details of offshore assets and services of politicians, businesses and celebrities, based on a cache of 11.5 million records.

Among the countries with past or present political figures named in the reports are Iceland, Ukraine, Pakistan, Saudi Arabia, Russia and Argentina.

Australia’s tax agency said Monday it was investigating more than 800 wealthy people for possible tax evasion linked to their alleged dealings with Mossack Fonseca, a Panamanian law firm with international offices that provide offshore financial services.