The revelation of the Panama Papers detailing the off-shore structures of many wealthy clients is a "crime" and an "attack" on Panama, the law firm at the heart of the scandal has said.

"This is a crime, a felony," Ramon Fonseca, one of the founders of the Panamanian firm Mossack Fonseca, told AFP.

"This is an attack on Panama because certain countries don't like it that we are so competitive in attracting companies," he said.

"Privacy is a fundamental human right that is being eroded more and more in the modern world. Each person has a right to privacy, whether they are a king or a beggar," he said.

A massive data leak from Mossack Fonseca's supposedly secure data centre resulted in media around the world gaining access to information exposing how wealthy politicians, celebrities and others used offshore listings to allegedly hide assets.

More than 11 million documents from the law firm were obtained by the International Consortium of Investigative Journalists and shared with media organisations around the world including the ABC's Four Corners program.

Mr Fonseca, who was an advisor to Panama's President Juan Carlos Varela until last month, described the extraction of the data as a "limited hack".

There was as yet no suspect in the leak, he added, and he declined to speculate until proof emerged.

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He stressed to AFP that Mossack Fonseca, which has been operating for nearly four decades and had created more than 240,000 companies, had never been "convicted or accused or any wrongdoing".

He also underlined that "we have no responsibility in how these companies were used", because the firm's role was as an intermediary.

"As we have so many companies, some have problems — that's normal," he said. "But we are not responsible for them."

AFP