The family of missing Nenagh student Stephen Cullinan have expressed their fears that he may have left Dublin and traveled to either Belfast or some other Irish city.
It is not believed that Stephen, 25, the son of North Tipperary IFA chairman Tim Ciullinan from Ballymackey, has left the island of Ireland.
The family's latest fears were raised as it is now 17 days since Stephen, a Computer student in the University of Limerick, and who was living in Castletroy, went missing.
Stephen was last sighted on St Stephen's Green in Dublin, and his father said that despite searching the city there had been no further sightings of him.
Mr Cullinan said it was "just a hunch" that Stephen may have gone to Belfast.
"He’s not in rural Ireland. I don’t believe he’d go back to Limerick or Cork where his brother lives. He could be in Galway. We’re grasping at straws," he said.
Mr Cullinan said that as far as the family was concerned, Stephen was still out there, and they were going to do whatever it took to find him.
"We’re not giving up," said Tim.
Stephen requires medication and the family is aware that he does not have his medication with him.
"He needs his medication. That’s the advice from his doctor. That’s our main concern - that he’s all right," said Mr Cullinan.
Stephen is described as 5ft 11in, of medium build with short, fair hair. He was last seen wearing a hoodie and jeans and wears glasses.
Mr Cullinan’s last contact with his family was on November 2 when he called his mother, Margaret.
His phone has since been switched off and cannot be traced.
The search for Stephen is being conducted by Gardai at Henry Street Garda station in Limerick and the public are urged to contact them on 061-212400 or any Garda station or the Garda Confidential Line on 1800-666111.