The Social Protection Minister Regina Doherty has said that legal people still have protection even if their mortgages are sold to a so-called 'vulture fund'.
Permanent TSB plans to sell 20,000 distressed loans at a value of around €4bn.
There have been calls for the government to block the sale at the majority state-owned bank, but Ministers say Permanent TSB does not have to seek the approval of the department to sell the loan book.
Minister Doherty said it is important that people know they have rights even if their mortgages are sold.
"I think anybody who thinks that their loan book is going to be moved from one investor, from one loan bank to another institution could potentially have concerns," she said.
"I think our job now, as a State, is to ensure that they have no need to have concerns - that there is legislation on our statute to make sure that, regardless of who your institution is, that the terms and conditions that you signed up to with your loan will not be changed, and cannot be changed."
The Government is being encouraged to take advantage of a unique opportunity to increase its housing stock and stop future evictions.
The Workers' Party is calling on the state to "think outside the box" and purchase the buy-to-let mortgages put on the market by Permanent TSB.
The party's Éilis Ryan says the move could secure the housing rights of thousands of tenants.
She said: "There are thousands of tenants living in rented homes who face eviction if the mortgage owned by their landlords is sold to vulture funds and many of those tenants don't know that they are in that situation because they don't receive any information in advance.
"What I think it shows is that we are plunged into a new housing crisis and we still haven't dealt with the results of the last housing crisis."