SIPTU is calling on the Government to implement rent controls.
The Service, Industrial, Professional and Technical Union has said it is a common sense approach to dealing with the immediate housing crisis.
The Minister for the Environment Alan Kelly is expected to unveil rental certainty measures in the coming weeks, after failing to agree measures before the Budget.
General secretary of SIPTU Jack O'Connor has said he does not understand why there has been such a delay in taking action.
“Quite frankly it seems a perfectly rational thing to do and we don’t understand why there is so much to-do about it,” Mr O’ Connor said.
“The simple reality is, even in a best case scenario, pursuing all the correct policies, the supply issue will not be met in the immediate future nor can it, because of its nature.”