Medical experts claim that stem cell research could lead to finding a cure for conditions such as Alzheimer's.
The European Commission's proposals would prohibit the use of embryo stem cells harvested after June 2002 and favour the use of stem cells taken from adults, which some scientists say is harder to work with.
The EU decided last year to fund the research, but member states issued a temporary freeze while the bloc's executive devised ethical guidelines.
Stem cell researchers will be able to dip into a 2.2 billion euro ($2.6 billion) research pot next year, though diplomats
reckon the European Commission is unlikely to award them more than 40 million euros.
But with the funding ban soon to expire, a minority of predominantly Catholic states at a meeting of EU research
ministers said the European Commission guidelines were too relaxed.
"It was decided to discuss the same question again next week," a diplomatic source said.
The source said he believed the ministers would be able to resolve their differences at a meeting on 3 December.
"The willingness to discuss again means there is space for an agreement," he said.
Failure to agree new ethical guidelines is unlikely to halt EU funding for embryo stem cell research, which is illegal in
some EU countries, as there would not be majority support for extending the funding freeze.