The number of homes advertised on Airbnb in the areas worst hit by the housing crisis rose by more than 1,000 last year.
That's despite new regulations aimed at clamping down on short-term holiday lets being brought in last July.
The number of entire homes advertised for short stays on the site rose in Dublin, Cork, Galway, Limerick and Waterford over the past year to 6,900.
Last July, new restrictions on short-term lettings came into effect, with the aim to make short term holiday letting less attractive to property owners.
Home-owners can only short term let their entire property for up to 14 days at a time, and no more than a total of 90 days in a given year.
Landlords are supposed to register such properties with their local authority, but the Irish Independent reports that just 370 applications to register have been received to date.
Local authorities are warning they are gearing up for a crackdown in the coming months, with Dublin City Council claiming to have issued 15 enforcement notices so far.
While 220 investigations into suspect lettings have begun.
The paper reports Dun Laoghaire Rathdown sent three warning letters, resulting in compliance from property owners.