Up to 5,000 landlords are to receive refunds after a change to a Government registration scheme.
The move means joint landlords will no longer have to pay multiple fees.
It is understood the decision to issue refunds was taken after the department received revised legal advice.
Social Development Minister Mervyn Storey said the process should be complete by next March,
He said: "It was clear the issue of multiple registration fees for joint owners was a concern amongst landlords when the Landlord Registration Scheme was launched; my department responded, and today I am announcing that not only will the policy change, but that we will soon be starting the process of issuing refunds."
The £80 Landlord Registration Scheme was launched in February 2014,
Of a total of more than 44,000 on the list, an estimated 8,500 are joint owner landlords.
Mr Storey added: "My department will complete this process of refunds as soon as possible and all joint owner landlords will be contacted directly.
"There is no need to take any action at this stage."