However, 2008 was characterised as being a 'very high year' for applications and so this year's drop is smaller than expected.
An Bord Pleanála says the number of planning applications it has received in 2009 is down by more than 30%.
It also argued that it had given warnings on residential over-zoning in recent years and described the extent of one-off housing in Ireland as 'alarming'.
Chairman John O'Connor said the unsustainable amount of one-off housing would have to be tackled in the years ahead.
Mr O'Connor also stressed that proper planning would continue to be applied in all cases and there would be no exceptions for deeply indebted projects expected to be dealt with by NAMA.
An Bord Pleanála says it had been ringing the alarm bells on residential over-zoning in recent years.
It said applicants to its Strategic Infrastructure Division were being too vague in proposals, with some applications not even site specific.
The board also called for a streamlining of local planning because 88 planning authorities for a population of nearly 4.5m people is too much.
