MEPs have called on the law firm at the centre of the Panama Papers leaks scandal to testify to Parliament.
The EPP group wants both Panama-based Mossack Fonseca and the Panama government to testify before a special committee on unfair tax practices.
The committee was set up after the so-called 'LuxLeaks' revelations.
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Burkhard Balz, the EPP group's spokesperson on the committee, said the move was necessary because the leaks represented "organised, large-scale parasitism."
Balz, a German deputy, said, "It is intolerable that both law firms and entire countries use living at the expense of other states as a business model."
"We want Mossack Fonseca and the Panama government to answer our questions in Parliament."
He warned of "further parliamentary consequences" as there will be "more revelations" published over the coming weeks.
He said, "We first need to gather all the information and agree on the next steps with all the political groups."
The EPP is the largest political group in Parliament, with 215 members from 27 member states.
Eleven million leaked documents showed how Mossack Fonseca clients were able to launder money, dodge sanctions and avoid tax. The law firm says it has operated beyond reproach for 40 years.
There are links to 12 current or former heads of state in the data, including dictators accused of looting their own countries.
The wife of EU Commissioner Miguel Arias Cañete is among those implicated.
Since 2009, many attempts have been made to crack down on abuses. More than 700 tax transparency deals have been signed globally.
Places including Switzerland, the Channel Islands and Luxembourg have tightened the rules, but others like Panama and the British Virgin Islands have been criticised for not doing enough.
Meanwhile, Mossack Fonseca has issued a stiff warning to the media outlets which leaked the documents.
A statement read, ''It appears that you have had unauthorised access to proprietary documents and information taken from our company and have presented and interpreted them out of context. We trust that you are fully aware that using information/documentation unlawfully obtained is a crime, and we will not hesitate to pursue all available criminal and civil remedies.''
This has prompted transparency campaigners to voice fears about the trade secrets protection directive, due to be voted on by MEPs on April 14.
Corporate Europe Observatory says the scandal shows the "need to safeguard press freedoms from proposed EU legislation."
The Brussels-based group's Martin Pigeon says the draft law would give companies like Mossack Fonseca "new legal ammunition" to prosecute journalists and news organisations publishing their internal documents and information.