The Pensions Board has said that it is a matter of serious concern that the number of people with occupational pension schemes has fallen by almost 40,000 since 2010.
Chief executive Brendan Kennedy said the active members of occupational pension schemes in April 2012 was 771,878, down 38,083 over 2010 levels.
The Board also revealed that it succeeded in 26 prosecutions of pensions law - with 36 more cases pending for 2012.
He said that while the fall in occupational pension scheme membership could be expected as a consequences of declines in employment and contractions in the economy, he said it was a matter of serious concern for the board given the importance of personal savings to provide for retirement in addition to the state pension.
Earlier this month the board published new rules for defined benefit pension schemes, 80% of which are in deficit.