Winifred (Winnie) Brady, 59, from Raheny, Dublin, had travelled to the village with a party of 10.
It was a place that she had visited twice before and knew well, according to her family.
Yesterday, local police searched in a circle around the house where Ms Brady had been staying before moving on to search the outskirts of Medjugorje.
A helicopter belonging to the EU peacekeeping commission was used on Wednesday to search for the woman.
It is planned to move the search into the hills over the coming days and the number of police involved is also expected to be increased.
The search team includes a special unit from Mostar who are trained in search and rescue.
Ms Brady’s daughter, Carmel Moody, said it appeared that her mother had just vanished last Wednesday.
Ms Brady left all her essential belongings, including her passport, money and medication at the house where she was staying close to the Marian Shrine.
On the day Ms Brady went missing she had decided against taking a trip to a mountain top religious site with the rest of her group because of a painful arthritic knee.
Ms Brady’s husband, Stephen, and other members of her family are in Medjugorje assisting the search for the woman.
Because no one saw her leaving the building where she was staying, no one knows in what direction she might have gone or what she might have been wearing at the time.