Detectives have been given a further 24 hours to question Lisa Smith.
The former member of the Irish Defence Forces was arrested on Sunday and is being questioned on suspicion of terrorist offences.
An armed escort brought Lisa Smith to a special sitting of Dublin District Court this morning, where an application to have her period of detention extended for a final 24 hours was granted.
Since her arrest on Sunday morning, detectives from the Special Detective Unit have been questioning her about movements and activities abroad.
The 38-year-old converted to Islam a number of years ago and married an Isil fighter.
Her 2yo daughter returned to Ireland with her and is being cared for by relatives, according to Gardaí.
She is being questioned under Sec 30 of the Offences Against the State Act.
The law allows for a total period of detention of 72 hours.
This latest extension means she can be detained at Kevin St GS until tomorrow morning when will either be charged or released without charge.
*Reporting by Frank Greaney