90 per cent of homes in Rent Pressure Zones across the country have failed to meet minimum housing standards.
Figures supplied to The Sunday Business Post by local authorites with RPZs show that 16,441private rental properties were inspected last year.
There's been a significant increase in the number of private rental homes being inspected by local councils, with 58 per cent more homes investigated in 2018 on the year previous.
The worst offenders were rental homes in Limerick City and County Council, Galway County Council and Louth County Council
None of the private rentals inspected passed the minimum housing standards.
County Wicklow homes fared the best, of 588 homes to come under scrutiny, 56 per cent met the standards.
Dublin City Council inspected the most properties, 3,561, of which more than 95 per cent failed.
Minimum standards require landlords to meet requirements such as structural repair, sanitation, heating, light, safety of gas and electrical supplies and absence of damp and rot.