Brussels hits out at 'nutty NGOs' and corporate sharks

"Lawyers involved in big competition cases try to get commercially sensitive information through the back door ... If they got it, the victims would go straight to court to sue us for millions and they would win," he said.

"Nutty NGOs say things like: 'Please send us details of every email, every phonecall or note ever written at any level on this subject from 2001 to 2006' ... When a desk officer writes a paper, they want to see it after he's written the first sentence before going on his coffee break," he added.

"As soon as our response comes, it goes in the bin and they send their next request. They think its funny to waste officials' time."

The commission in 2008 put out draft new rules to replace a 2001 regulation on the subject.

It put out another draft in 2011 to extend existing rules to all EU institutions, such as the European Central Bank and EU agencies.

Both bills are being blocked by the EU parliament, which says they are a step backward on transparency, however.

"We have said over and over that every document, every single sentence that would have been released under the old regime would still be released under the new one ... We are just trying to bring extra clarity. The debate is infantile and some people need to grow up," Gravili said.

Diplomats from EU member states will on Friday debate a new Danish EU presidency proposal designed to end the stalemate.

A contact familiar with the Danes' latest draft said it has more relaxed wording on documents in competition cases, infringement procedures, appointment of senior officials and legal advice from EU institutions.

While the previous draft spoke of "block exemptions" for the papers, the new version says the documents "shall be presumed as being" out of bounds if the EU institutions can demonstrate it would cause harm to release them, shifting the burden of proof from applicants to officials.

A small minority - Estonia, Finland, the Netherlands and Sweden - are pushing for what they say is more transparency. But the majority of member states want to see tighter rules.

A Swedish contact noted: "We still don't like it [the new draft], but it's better." An Estonian source said: "We do agree that it is better. But we should keep in mind that the Lisbon Treaty clearly demands more transparency."

If member states endorse the new Danish draft on Friday, Denmark will resume talks with MEPs next week.