Panama's attorney general's office issued a statement revealing that it had carried out a raid on Mossack Fonseca's office to search for evidence of illegal activity.
The statement, which was reported on by Reuters, remarked that the authorities were looking for documentation that "would establish the possible use of the firm for illicit activities".
Earlier this month, the International Consortium of Investigative Journalists (ICIJ) published a report based on more than 11m leaked files belonging to Mossack Fonseca, which implicated a number of high-profile figures in offshore tax dealings.
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In an interview with German newspaper Bild on Saturday, the firm's founding partner Ramon Fonseca said that Mossack Fonseca was still waiting to be contacted by the authorities.
"Every time there's something in the newspapers, the authorities announce they'll launch investigations," he said. "We're fully cooperating but we haven't been contacted by anyone yet."
Many authorities across the world jumped into action to launch their own investigations following the leak. In the UK, HM Revenue & Customs (HMRC) confirmed the day after the report was published that it has requested access to the information that the ICIJ had received.
Mossack Fonseca did not respond to City A.M.'s request for comment.
However, a statement on Mossack Fonseca's website remarks that, in the almost 40 years that it has been up and running, it has never been charged with criminal wrongdoing.