A report by Davy Stockbrokers on the housing market has said one third of Irish housing output is going towards satisfying demand for second homes.
It also says further rapid rises in house prices are unlikely.
The report - by economists Colm McCarthy, Annette Hughes and Ernestine Woelger - also argues that too much has been made of demographic factors in attempts to explain the record growth in housing activity in the past decade.
It says new households are likely to account for less than 50% of the 67,000 new houses the report forecasts will be built this year.
The report says affordability has improved despite the rapid rise in house prices relative to incomes, reflecting falling mortgage rates.
The economists say the risk of a fall in house prices has increased, and further rapid rises are unlikely.
They argue that either higher interest rates, or weaker labour market and consumer confidence, will hit demand for housing. The report also says the current level of house completions will not be maintained.
