Hap refusal - Section 21, Equal Status Act, 2000

A landlord can rent a property to whoever they want. They do not have to give it to someone just because they can get Hap. 

 
They are not allowed to refuse someone though just because they receive Hap or want to.

Every potential tenant is supposed to be treated the same, whether they receive Hap or not.

Under the Equal Status Acts it is against the law for your landlord / letting agent to refuse to accept Hap.

An interesting case about this matter can be read here.