The Police Service of Northern Ireland (PSNI) have instructed Sydney police to detain a man in his 30's from County Armagh.
The man in question was arrested on suspicion of the murder of Thomas O’Hare, 33, and his girlfriend Lisa McClatchey, 21, from Tassagh, near Newtownhamilton, in 2006 according to the Irish Echo newspaper.
The couple were attacked in their home before it was doused in petrol and set alight.
The suspect is currently being detained by Sydney police. He will apear in court today where he will face extradition proceedings.
Two brothers were previously charged in connection with the couples murder and setting fire to the property.
The Irish Echo says more on these developments will follow.