The Taoiseach says he is satisfied with plans put in place to care for Lisa Smith's child when the pair return to Ireland.
The 38-year-old Dundalk woman travelled to Syria in 2016 to join the so-called Islamic State group.
She's currently in Turkey, but is expected home within the next week.
Ms Smith and her daughter were transferred to Turkish custody following the bombing of the Ain Issa displacement camp in north-east Syria in recent weeks.
Leo Varadkar says her two-year-old daughter is an Irish citizen who should be looked after.
Speaking in Templemore today, the Taoiseach said: "It is a tricky situation, and ultimately the child is an Irish citizen - and deserves to be protected in my view.
"Obviously as regards Lisa Smith, that's a slightly different situation - but she is our citizen, and it wouldn't be fair to expect the Turkish authorities to hold her indefinitely."
Mr Varadkar added: "As an Irish citizen, [Lisa Smith] is free to return home to Ireland - but if she does return home the gardaí are going to want to talk to her.
"We need to ensure that the child's welfare is protected. Of course there are relatives who are in contact, but also Tusla are aware that that situation may arise."
