Landlord Action has been campaigning against the rises for almost three months and has actively encouraged complaints from landlords.
However it warned that whilst it is encouraged by the decision there are still many buy-to-let borrowers facing rises three times their existing monthly payment.
Paul Shamplina, founder of Landlord Action, said: “The Bank of Ireland has reversed its mortgage rate increase for over a thousand borrowers and it’s all because we all complained. This is landlord power and this should be a lesson to all landlords.
“Lenders have the power to try it on and then wait to see what happens. However under the regulations the banks are obliged to look into every single complaint so their decisions must always be challenged.
“We stand by our advice - if you are being unfairly treated, complain, complain, complain. This BoI decision is proof that it can work.”
Landlord Action said it is still looking into the cases for the remainder of the affected borrowers but would like to thank all those landlords who came forward and put their names in to a group action.
“It's because of people like them that the bank has backed down. We believe that many more borrowers could benefit with a bit more effort," he concluded.
