Finance ministers of several European Union countries expressed reservations Saturday over new tax laws proposed amid pressure to increase transparency in the wake of the Panama Papers, the biggest leak of confidential data in recent history. EU officials had called for the rules to force multinational companies to publicly disclose their activities in tax havens.

The draft, proposed on April 12, faced protests from companies that said some data may be misinterpreted if made publicly available, hurting their reputation. Non-EU firms could also acquire valuable information on their EU competitors, trade associations have said.

"We would prefer that as a first step, [corporate tax data] should be available to tax authorities, not to the public," Maltese Finance Minister Edward Scicluna said Saturday in Amsterdam. EU finance ministers are holding a two-day meeting in the Dutch capital.

Netherlands Finance Minister Jeroen Dijsselbloem reportedly said he favored public disclosure, but added: "Some are worried [public disclosure] will damage the competitive advantage of Europe."

Regional tax authorities in Germany have warned that extra transparency requirements might undermine efficiency, German Finance Minister Wolfgang Schäuble said. Getting taxpayers to disclose their finances “works better if you don’t have to fear the public pillory effect,” he added.

“Many countries are of the opinion that this should be left at the level of finance authorities,” Austria's Finance Minister Hans Jörg Schelling reportedly said.

The proposed tax rules would force companies with annual revenues above 750 million euros ($842 million) and those which operate in the EU to disclose their tax affairs to the public. The draft widened the scope of the disclosure rules to include funds parked in countries, which are often described as tax havens, due to mounting public anger after leaked documents from Mossack Fonseca, a Panamanian law firm.

The Panama Papers contain tax details of hundreds of thousands of clients in more than 11.5 million documents. The papers, which span nearly 40 years, from 1977 through the end of 2015, allegedly show that some of the companies were being used for suspected money laundering, arms and drug deals and tax evasion.