The prosecution sought 12-year prison sentences Wednesday for the founders of a now-defunct law firm at the center of the so-called "Panama Papers" tax evasion scandal.

Jurgen Mossack and Ramon Fonseca stand accused of money laundering in a trial that opened against them and more than two dozen others, mainly former employees, in a court in Panama City last week.

The 2016 leaks revealed how many of the world's wealthy stashed assets in offshore companies, exposing high-profile personalities and triggering scores of investigations around the globe.

Mossack, 76, said at the start of the hearing he was not responsible for alleged crimes.

Prosecutor Isis Soto Wednesday asked the court to impose the maximum sentence against the pair for money laundering, which in the Central American country is 12 years.

Mossack and Fonseca are also accused of "concealing, covering up and providing false information to banks for the opening of accounts and concealing ownership of assets," said the prosecutor.

"Jurgen Mossack and Ramon Fonseca... received and transferred funds from illicit activities in Germany and Argentina," added Soto.

The leaked trove of 11.5 million files from the law firm Mossack Fonseca implicated influential figures including billionaires, politicians and sports stars.

Icelandic prime minister Sigmundur David Gunnlaugsson was forced to resign after it was revealed his family had offshore accounts.

Then Pakistani prime minister Nawaz Sharif was disqualified from office for life after being implicated in the documents.

Others implicated included former British premier David Cameron, football star Lionel Messi, Argentina's then-president Mauricio Macri and Spanish filmmaker Pedro Almodovar, to name but a few.

The files were leaked to a German newspaper, Sueddeutsche Zeitung, which shared them with the International Consortium of Investigative Journalists.

Many of those caught up in the scandal put forward reasons to explain their offshore presence and said they did not act illegally.

Even so, Mossack Fonseca said in 2018 that it would close due to "irreparable damage" to its reputation.

The scandal dealt a severe blow to Panama's image as an offshore financial hub.

Defense lawyer Dionicio Rodriguez has argued that "activities are being prosecuted that are legal in many other countries in the world."

The fact that some of its current laws against money laundering did not exist when the Panama Papers revelations emerged could complicate efforts to achieve convictions, according to legal experts.

In 2023, Mossack and Fonseca were tried in Panama for alleged money laundering in Brazil's "Car Wash" corruption scandal involving construction group Odebrecht.

The prosecution requested up to 12 years in prison for both in that case. No sentence has been pronounced.