The number of new homes registered last month fell by 60 percent compared with the same month last year, according to figures from home guarantee scheme Homebond.
Homebond said just 45 new homes were registered across the country last month, down from 72 in January last year.
No new homes at all were registered in Dublin. Two counties, Louth and Cork, accounted for more than two-thirds of the total.
The Homebond figures are seen as an indicator of future housing activity. Homebond is the bigger of two companies which provide registration figures, the other being Premier.
Last month, Homebond figures showed that the number of new homes registered last year fell by more than 50 percent compared with 2010.
Meanwhile, activity in the Irish construction sector fell again at the start of 2012, after stabilizing towards the end of last year.
The Ulster Bank Construction Purchasing Managers' Index fell to 46.4 in January from 49.9 in December. Any figure below 50 signals contraction, while a figure above 50 signals growth. The index looks at three components of the industry -- housing, commercial and civil engineering.
The bank said that in contrast to the trend for overall activity, commercial activity increased in January from 49.8 to 51.3. The rise was the first in the sector since October 2007.
Housing activity fell in January, with the index falling to 47.2 from 52.3 in December, while civil engineering remained the worst performing sector, with activity seeing a steep reduction to 37.7 from 42.9 in December.
Ulster Bank said January saw the fastest reduction in activity in three months with companies reporting falling new business due to weak client confidence amid uncertain economic conditions.
Jobs continued to be cut sharply in the sector, but construction firms decreased their purchasing activity at the weakest pace since January 2011. Sentiment regarding future activity levels also improved.