Update: Threshold says its surprised to see the number of entire homes available on Airbnb has increased since new regulations were brought in.
The housing charity said new rules designed to make short-term letting less attractive need better enforcement.
The number of days homeowners can rent out their entire home is restricted to 90 days a year and they must register with their local authority.
Threshold's Stephen Large said they want to see swift action against those breaching the legislation.
Mr Large said: "Well I think enforcement is key and it appears the local authorities are ramping up their resources to enable them to do that.
"What we would stress is that these breaches be inspected and that they are enforced sooner rather than later because we need more private rented accommodation."
Sinn Féin's housing spokesperson Eoin Ó Broin has called on Minister Eoghan Murphy to fine Airbnb and other platforms for advertising rogue properties.
"New short-term letting regulations came into force in July 2019, and to date the vast majority of short-term letting landlords continue to flout the law.
"We now learn that there has been a significant increase in the number of short-term lets available at a time when long-term rental supply continues to fall well below demand.
"There is no point in introducing regulations for the short-term letting sector without adequate enforcement."
The number of entire homes listed on Airbnb increased by more than 1,000 last year in areas worst hit by the housing crisis.
The news comes despite new rules aimed at making short-term letting less attractive to homeowners.
The number of homes advertised in Dublin, Cork, Galway, Limerick and Waterford increased to 6,900 according to the Irish Independent.
In July, new rules were put in place in an attempt to make short term letting less attractive.
The aim was to bring more properties back into the rental market.
As of last year, short term lettings are obliged to register with their local authority. However, just 370 applications have been received nationwide.