Research by Daft.ie. found there were differences in trends across regions.
Rents in the second quarter of this year in Ireland were an average of 5.6% higher than the same period in 2020, according to latest figures.
The average monthly rent stood at 1,477 euro in the second quarter of 2021, up 2.4% on the first three months of the year and almost 99% from a low of 742 euro per month seen in late 2011.
There continues to be significant differences in trends across regions, a rental report by Daft.ie. found.
In Dublin, rents rose for the second consecutive quarter, by 1.4% between March and June, but are just 0.5% above the level seen a year ago.
Other cities, however, have seen much larger increases – rents in Cork, Galway and Limerick cities are between 9% and 10% higher than a year ago while in Waterford they are nearly 12% higher.
The report found that outside the cities, rents rose by 8.6% in Leinster, by 13.7% in Munster and by 14.7% in Connacht-Ulster.
The sharp increases in rents reflect an unprecedented scarcity of rental homes, the report said.
Nationwide, there were just 2,455 homes available to rent on August 1, an all-time low in a series that extends back to January 2006.
On average over the past 15 years, there have been nearly 9,400 homes available to rent at any one time while the 2015-2019 average was almost 3,900.
While the number of homes available to rent in Dublin is down 44% year-on-year, it is close to levels seen in 2019.
Outside Dublin, however, there were just 789 homes available to rent, by far the lowest on record – prior to 2020, the lowest level had been just below 1,500.
Ronan Lyons, economist at Trinity College Dublin and author of the Daft report, said: “As the impact of Covid-19 on daily life begins to recede, the underlying issues facing Ireland’s rental sector are re-emerging.
“It is a sector facing unprecedented shortages, with extraordinarily tight supply: to give just two examples of many, there were just 15 homes available to rent in Waterford, city and county, on August 1 and only eight in all of Offaly.
“Ireland’s rental sector has undergone a lost decade and half, with almost no new rental homes built.
“This cannot be solved by trying to regulate prices. It can only be solved by adding significant amounts of new supply – and not only in Dublin.
“In that regard, policymakers – and citizens – should be wary of anything that limits the ability of foreign savers to build new rental homes here.”
A spokesperson for the Department of Housing said: “The Housing For All plan to be published shortly will build on commitments in the Programme for Government and provide a road map, with a whole-of-government approach, towards a housing system that gives us the sustainable supply we need, at a price that people can afford, with appropriate options for all.”
“The Government has recently enacted significant legislation which will mean rents in Rent Pressure Zones – 74% of all tenancies – will now be allowed to rise only in line with inflation,” the spokesperson said.
“On top of this, for those outside of Rent Pressure Zones, the provision for rent reviews every two years will be extended for an additional three years.”
The spokesperson said that the Government is “committed” to developing a “cost rental model” in Ireland and had also enacted the Affordable Housing Bill 2021 for renters who want to own their own home.