Axa, the French insurance group that has been one of the most enthusiastic supporters of the rules, also said it stood firmly behind the CEA's position.
It is not just insurers expressing concern. The Association of Corporate Treasurers in the UK has warned that the rules will hurt companies' ability to borrow and could harm the economy.
"The proposals as they stand will, we believe, reduce the willingness of insurance companies to invest in corporate [debt], which will have a negative effect on the real economy," said John Grout, policy and technical director of the ACT.
Jim Bichard, a partner at PwC, said Ceiops had gone beyond the provisions of the framework passed in the European parliament in April and its advice could put an even more costly burden on the industry in terms of compliance.
The Commission has to complete its drafting of the next stage of the rules by the end of next year. Some believe it has already become sympathetic to industry concerns and will ignore Ceiops' advice.
However, assessing attitudes in Brussels is complicated because a new Commission will almost certainly be in place next year, with associated personnel changes. Commission officials say only that the matter is at a very early stage, and that it is for Ceiops to consider.
Tidjane Thiam, chief executive elect of Prudential, said in an interview with the FT last week that the task of designing a single regime for many different companies across 27 different countries was was almost certain to create a system that was wrong for everybody.
"If you take a one size fits all approach, you're almost certain to be wrong for everybody," he said. "It's intellectually very attractive because ... we like elegant solutions, but there are lot of elegant solutions that don't work very well."