Financial Services Ombudsman Bill Prasifka is appearing before the Oireachtas finance committee for the first time.
Mr Prasifka, who is now in the position for four years, said the most recent review by his office noted an "improvement in the work of financial service providers".
He said the office has "tightened procedures in relation to accepting complaints".
Since 1 September, the substance of complaints have been given to financial service providers - giving the provider a chance to respond, he said.
Mr Prasifka told the committee that this has led to a lot more engagement between providers and their customers than in previous periods.
The ombudsman said additional reporting power has led to increased interest in financial service providers. He said the medium and long-term significance of these changes "remains to be seen".
He also outlined reasons why mortgage holders affected from the sale of IBRC's loan book would not have a right to complain to his office if the loans are sold to a non-regulated buyer.
Mr Prasifka was responding to Sinn Féin's finance spokesperson Pearse Doherty.
Mr Doherty put it to the ombudsman that he was in dispute with Minister for Finance Michael Noonan, who said the ombudsman was entitled to carry out investigations.
The ombudsman said it was "firmly grounded in legislation". Secondly, he said, "it would be operated as a significant threat to future of the office and I was not prepared to do that".
Mr Doherty asked if Minister Noonan and Mr Prasifka had sat down and discussed the matter.
Mr Prasifka said: "There have been many discussions and exchanges with the minister".