Researchers from the Alliance for Lobbying Transparency and Ethics Regulation (ALTER-EU) requested lists of all meetings held with lobbyists in 2015 from 17 EU member state permanent representations.
Yet the investigation revealed only four governments – Ireland, Romania, the Netherlands and Poland – were able to provide all or some of this information.
Companies including 'shared economy' taxi giant Uber, multinational financial service provider Morgan Stanley, Ikea and tobacco company Philip Morris were among the companies listed. Food and personal care giant Unilever also featured in the report - but the company declined to comment on its meetings with Romanian and Dutch representatives.
The report claimed industry was exploiting a loophole in EU transparency rules which enabled them to lobby permanent representations without being registered in the EU transparency register.
ALTER-EU is a coalition of over 200 public interest groups concerned with what they call an “increasing influence exerted by corporate lobbyists on the political agenda in Europe”.
It was now calling for a legally-binding EU lobby register that includes all EU institutions and permanent representations.
Andreas Pavlou, campaigner and researcher at ALTER-EU member Access Info Europe, said: “The review of the EU lobby register must ensure full transparency around the development of rules and regulations that ultimately affect the lives of 500 million European citizens.
“To find that many permanent representations do not even keep a record of lobby meetings and, in some cases, even refuse disclosure of this basic information is shocking.”
According to the report, Belgium, Denmark, Germany, Portugal, Spain and Sweden said they didn't have any information.
The UK and Malta refused to grant access to any lobby information, while Austria, Cyprus, France, Greece and Italy did not respond despite repeated requests.
Vicky Cann, a campaigner for ALTER-EU member Corporate Europe Observatory, said: “These national government offices play an important role in EU decision-making but in a way which is largely under the radar, making them an ideal target for big business lobbyists.
“It seems clear that member state offices in Brussels are wide open to corporate lobbyists.”
Yet not everybody agreed a crackdown was the answer.
A European Parliament source told us these representatives played an important role in scoping out all sides of arguments and helping Members of European Parliament (MEPs) make informed decisions.
He said recording every meeting “would be absurd” and could even force discussions underground.
“Lobbying is quite legitimate as long as it is conducted openly and without bribery or other incentives. If a sensible MEP or her/her assistant receives lobbyists and listens to them, he/she can make up his/her own mind as to what the best course of action is.”
The European Commission did not respond to our request for comment in time for the publication of this article.