Simon Harris said legislation related to fatal foetal abnormalities in this country is "utterly unacceptable"
The Health Minister says people need to think beyond the words 'Repeal The Eighth' and consider what that would mean.
It comes as the Dáil prepares to debate a bill this week that would allow abortions in the cases of fatal foetal abnormality.
Fianna Fáil TDs will get a free vote on the bill.
Simon Harris says he believes the bill being brought by Deputy Mick Wallace is unconstitutional.
He said there needs to serious thought into what repealing the Eighth Amendment of the Constitution would mean.
Speaking to Pat Kenny, Minister Harris said he believes the legislation related to fatal foetal abnormalities in this country is "utterly unacceptable".
However, he also said: "What does the world look like after [repealing]? What does the legislation look like after that? Is there constitutional protection?
"These are extraordinarily complex, and that's why I really do believe the Citizens' Assembly will provide the space to have informed debate," he added.
The Cabinet last week approved plans for a Citizens' Assembly on abortion and other issues.
The 100-member group will hold its first meeting before November, and be given 12 months to complete its work.
However, it is understood the assembly will be allowed to complete its work in modules, with the Eighth Amendment the first issue on its agenda.