The Chair of the Oireachtas Finance Committee says Permanent TSB should pass discounts on bad mortgages on to customers.
John McGuinness argues they could get more money from restructuring current deals rather than selling the loans to vulture funds.
The bank wants to sell around 18,000 bad loans.
Finance Committee chair John McGuinness said that there has to be a better way.
"Maybe the customer might pay you more than what you will receive from the vulture funds in order to restructure a loan," he said.
"So why not give them the benefit of what you're about to do and allow them to stay in their home and pay a restructured loan?" he said.
"That's debt forgiveness, and we don't do debt forgiveness," said Permanent TSB chief executive Jeremy Masding.
Permanent TSB says it has no option but to sell non-performing loans pic.twitter.com/CAK56PuGWB
— RTÉ Business (@RTEbusiness) March 22, 2018
Permanent TSB says it takes an average of 32 attempts to get in contact with mortgage holders in long-term arrears.
Management at the bank has been appearing before the Oireachtas Finance Committee about the proposed sale of almost 18,000 loans.
The bank says it's a necessary move to shed non-performing loans from their books.
Shane O'Sullivan, PTSB's group director of operations, says many of those in long-term arrears have been difficult to deal with.
"On average it takes us 32 attempts for a customer to speak to us in this category about their mortgage. That's an average figure that's not a high or low figure, so on average it will take 32 attempts for us to speak to the right party about the debt that's owing."
The head of Permanent TSB says vulture funds are not pursuing mortgage holders any more aggressively than Irish banks.
PTSB plans to sell €3.7bn worth of troubled loans in the coming months.
There are fears many mortgage holders may end up with their loans being owned by vulture funds.
However, PTSB boss Jeremy Masding says people will still be protected if that happens.
Mr Masding said: "Since our announcement, much of the commentary has focused on customer protection when the loans are sold, but as the Governor of the Central Bank of Ireland confirmed in recent weeks, where a loan is sold the protections travel with the loan.
"Of course thousands of such loans have already been sold by a variety of banks in Ireland.
"And as the Governor pointed out, the evidence today does not support the narrative that these buyers are managing these loans any more aggressively than the original banks were."