The average rent nationwide is 9% higher than it was at the same time last year, according to the latest quarterly rental report by property website Daft.ie.
Dublin city saw the biggest annual increase in rent of 14%.
There were 10,000 rental properties advertised in the first four months of this year in Dublin.
That compares to 18,000 in the same period in 2012.
The shortage in accommodation across the capital has seen rents increase by 22% in three years.
They are now 13% below peak values in 2007.
Rents rose in all cities, with Cork and Galway experiencing a 6% rise, Limerick 5% and Waterford 1%.
Rents in Dublin's neighbouring counties of Wicklow and Kildare also witnessed a significant increase of 9%.
Rents rose by an average of 4% outside cities.
The number of properties available for rent outside cities is now under 4,000, which is down from 11,000 two years ago.
The report's author has warned that rental prices are now approaching the levels they were at the peak of the boom.
Trinity College Assistant Professor of Economics Ronan Lyons said that a lack of supply means that there is now a housing crisis, especially in the capital.
Speaking on RTÉ's Morning Ireland, Mr Lyons said that supply in Dublin needed to quadruple, otherwise those on lower incomes would be squeezed out of the market.
Chief Executive of the housing charity Threshold has said people at the lower end of the rental market are facing rent increases of between 30% and 50%.
Speaking on RTÉ's Six One News Mr Jordan said the private rental sector was a much bigger sector than it was before one in five families lived there, and these families could ill-afford to up-sticks every year because they are facing a huge rent increase.
Mr Jordan said landlords were entitled to make an income out of renting, but they were not entitled to make super-normal profits out of the misery of other people.
Mr Jordan also said that the fact that there are thousands of vacant local authority housing units around the country is totally unacceptable.