Growth in house building activity had slowed before the onset of the Covid-19 construction closures, according to the latest tracker from Goodbody Stockbrokers.
The rate of growth in the first three months was the slowest since the end of 2013, economist Dermot O'Leary said.
New home completions were up 6% at 4,500 units in the period, but are now expected to fall sharply for the full year.
Goodbody said that given the current shutdown, coupled with expected social distancing measures when sites reopen and the changed economic environment, it is expecting a significant fall in output for the rest of the year.
Output for the full year is now likely to be below 2018 levels of 18,000.
Today's figures show that completions in the greater Dublin area fell by 4% in the first quarter of 2020, with completions in the rest of the country increasing by 21% year on year.
Within this, completions in Dublin's commuter counties fell by 12%, which Goodbody said marked a significant deterioration from the last five years of rapid growth.
Completions in Dublin grew by just 2% in the first quarter of the year.
Growth in completions was led by the West with reported growth rates of 63%, while completions in the Midlands jumped 56% and rose by 18% in the Mid-West, although these are all from much lower bases.
Goodbody economist Dermot O'Leary said the restrictions to halt the spread of Covid-19 have already had a large impact on the labour market and the wider economy.
"As attention turns to how to safely reopen the economy, it is likely the Government will want construction, and housebuilding in particular, to be among the first industries to reopen, albeit with added safety precautions," Mr O'Leary said.
"However, the demand environment will be impacted negatively, and is likely to result in a reassessment of supply plans by some developers," he added.