Independent Alliance minister John Halligan has compared child mortality rates in mother and baby homes to Nazi concentration camps.
The Waterford TD also said religious orders found guilty of criminal neglect should have their assets seized.
The Minister of State for Training and Skills said elderly nuns who worked in the homes should be interviewed as part of expected criminal investigations to be conducted by gardaí.
“Old age should not diminish accountability for any crime or alleged crime. If you bear in mind that the child mortality rate at Bessborough in 1943 was approaching 70 per cent, sure that’s similar to concentration camps,” he said.
"Are we seriously saying that because somebody is ill or aged that we shouldn't at least interview them? If you look at what's happened at Belsen, Auschwitz, Dachau, even up to last year individuals who are alleged to have carried out horrendous crimes in their 80s and 90s were interviewed."
Mr Halligan was speaking to RTÉ Radio on Saturday in the wake of confirmation last week from the Mother and Baby Homes Commission that "significant quantities" of human remains found at a mother and baby home in Tuam run by the Bon Secours Sisters belonged to young infants.
Minister for Children and Youth Affairs Katherine Zappone is said to be considering broadening the commission of inquiry's remit to include other homes beyond Tuam, and will examine her options over the coming weeks.
Referring to State grants paid to the Bon Secours order for maintenance of children in its care as well as sums received through the sale of children to foster parents in the US, Mr Halligan said monies should be seized if significant wrongdoing is established.
"I think there has to be an investigation, everybody has to be interviewed, and if it is found that they're guilty of neglect, well their assets should be seized by the Criminal Assets Bureau, " he said.
Speaking on the Claire Byrne programme David Quinn, head of Catholic advocacy group the Iona Institute, said the lack of comment on the topic from the Bon Secours Sisters was "not helping matters".
“One point of frustration for the whole thing is that the Bon Secours sisters have said so little.... I would love to hear more from the Bon Secours sisters, and I think their silence is not helping matters to put it mildly,” he said.
Mr Quinn agreed that nuns who are suspected of engaging in criminal neglect should be interviewed as part of investigations.