The Irish Financial Services Regulatory Authority has asked the boards of several credit unions to take "remedial action" to deal with unusually high levels of bad debt on their loan books.

The credit unions in question have not been publicly identified, but each was among 26 that were told to scrutinise their books during the summer after a new reporting scheme raised questions about their bad debt profile.

The regulator's spokesman said the body is "engaged in constructive dialogue with these credit unions to help ensure that the issues that were of initial concern are being addressed", but he would not comment on the nature of the remedial action being sought.

However, it is likely that the credit union boards were told to take specific measures to improve their position within a set period.

"As reported, the financial regulator wrote to the boards of a number of credit unions earlier this year requesting them to review their loan books, particularly in relation to levels of non-performing loans, levels of provisions set against those loans and related issues," the regulator's spokesman said.

"The credit unions concerned were requested to report back to the financial regulator. All credit unions contacted have now reported back."

The spokesman said the regulator's engagement with the credit unions in question will form part of its ongoing regulatory work. "The financial regulator will work closely with these credit unions in order to ensure that all of the matters identified are resolved," he said.

The bad debt problem in the credit union movement was highlighted in an internal report for the Irish League of Credit Unions, which warned that some of its 530 unions will probably go out of business because members were not repaying their loans. A large number of credit unions were ignoring their bad debt issue or were not aware of their problem, it said.

In addition, the report said the current degree of delinquency - the failure to repay loans - in some credit unions increased the risk to the movement in terms of its "potential impact" on the insurance fund, known as the Savings Protection Scheme.

When the report was made public last May, the league said the three million people who have €12.6 billion in savings with the credit union movement had no reason to be concerned about their funds.

However, the report of the league's own rationalisation committee cited a 2003 analysis, which said that the ratio of loans not being repaid was in breach of the league's own targets in 72 per cent of 448 credit unions surveyed.