A housing charity says some landlords are getting around rent pressure zone rules because of a lack of enforcement.
A new report from daft.ie shows rents have increased 11.5% nationwide in the first three months of the year.
Monthly rents are now over €200 more than they were in 2008.
Stephen Large from Threshold says it is a frustrating situation.
"It's a housing crisis and there is a severe lack of supply out there," said Mr Large.
"We have to address that imbalance, we have to increase supply. But in the interim, we need to protect people in their current circumstances.
"One of which is to enforce the RPZ rules and limiting rent increases to 4% and where there is a breach that action is taken."
- Digital Desk