Lisa Smith holding her daughter while speaking to CNN Photo: CNN
"She may become the target of those who have suffered at Islamic State's hands or those who are violently opposed to Isil, to the extent they want to take it into their own hands," Mr Roberts said.
Mr Roberts said Ms Smith would be seen as "damaged goods" by Islamic terrorists if she does return and it is unlikely she will be used to set up a terror cell in Ireland.
"Ultimately, one would hope there is a prospect of de-radicalisation and she could be turned in another direction and act as a warning to those who are tempted by the idea," he said.
"She could actually cause damage to the causes of the Islamic State," he added.
Taoiseach Leo Varadkar has said Lisa Smith and her two-year-old daughter will be allowed to return to Ireland - but a full security assessment into her situation will take place. The International Red Cross is spearheading the operation to bring Smith, a former member of the Defence Forces, back to Ireland.
She is currently in a detention camp in north-eastern Syria where conditions are extremely poor. Lisa Smith was interviewed in the Al-Hawl refugee camp by CNN last week when she said that she "wants to go home".
Asked if she was concerned about being imprisoned on her return to Ireland, she said: "I know they'd strip me of my passport and I wouldn't travel and I'd be watched kind of, but prison? I don't know. I'm already in prison."
She also said people "should realise that all the people here [in the camp] are not terrorists".