In a five-page letter sent on December 15 to European Commission President Jose Manuel Barroso, the heads of the companies accused Hungary, which on January 1 took over the EU's rotating presidency, of imposing exceptional taxes on them, daily newspaper Die Welt reported on Monday.
Among the companies who sent the letter were energy groups including Germany's RWE and EON, Czech firm CEZ and Austria's OMV, as well as Dutch financial groups ING and Aegon, French insurance giant AXA and Germany's Deutsche Telekom.
The letter reportedly urged the EU's executive Commission to put pressure on the Hungarian government to make it abandon its decision to impose "unjust financial millstones" which, the newspaper reported, cost Deutsche Telekom about €100 million ($134 million) in extra taxes last year at its Hungarian subsidiary Magyar Telekom.
The firms said the Hungarian government was bringing in an extra €1.3 billion by charging the special tax on large companies.
Germany's Economy Minister Rainer Brüderle was also critical of the tax, telling the Monday edition of Süddeutsche Zeitung: "Taxes that predominantly affect foreign companies are fundamentally a problem for the internal European market."
He said he had raised the issue with Budapest and that it would be on the agenda for a meeting with his Hungarian counterpart Tamas Fellegi later this month.
Süddeutsche Zeitung also quoted a European Commission spokeswoman as
saying the issue was being given "the highest attention" and that if Budapest was found to be violating European rules, "formal proceedings" would be opened against it.