Daniel Snedden rejects the allegations outlined in Croatia's extradition request that he committed war crimes as the commander of a Serb paramilitary unit in the 1990s.
He launched his first legal challenge to the Australian government's approval of the order in 2006, and the federal Attorney General's Department says he has exercised his right to challenge the extradition process in 12 separate matters.
Mr Snedden, who is also known as Dragan Vasiljkovic, or Captain Dragan, remains detained without charge in Sydney's Parklea Prison.
The federal Attorney General's Department has told SBS that the Commonwealth government has to date incurred around $950,000 in legal expenses responding to Mr Snedden's court challenges.
That's in addition to around $500,000 it cost the Australian Federal Police (AFP) to find him when he went missing for several weeks in 2010.
Based on data from NSW Corrective Services, it's estimated that his imprisonment has cost the New South Wales government over half a million dollars.
Luka Budak, from the United Croatian Clubs and Associations of Australia and New Zealand, says it's a financial burden taxpayers shouldn't have to bear.
"I'm really stunned to hear that kind of money has been spent on this case. As a taxpayer this is incredible. I think our federal government has a lot of other better projects to spend the money on," he told SBS.
Before the full Federal Court, Mr Snedden's lawyers are attempting to have the order thrown out on procedural grounds - arguing, in part, that it's taking far too long.
Journalist Mark Aarons, who has written extensively about the presence of alleged war criminals in Australia, says: "Vasiljkovic in this case deserves a considerable part of the discredit for postponements … and he has only got himself to blame for pursuing those legal avenues. But the courts themselves … have contributed significantly to the delays and the politicians have been the cream on the top of that."
The protracted Snedden case is blocking an extradition request from Croatia for a second Australian man.
Croatian authorities revealed that a criminal proceeding has commenced concerning Melbourne man Predrag Japranin, who they allege may be linked to the killing of civilians during the Croatian war.
Mr Japranin reportedly rejects the allegations against him.
But Croatia's Justice Ministry told SBS it would hold off on a formal request for Mr Japranin's extradition until the Snedden case is resolved.
Melbourne-based Gideon Boas was a lawyer for the prosecution at the International Criminal Tribunal for the former Yugoslavia in The Hague when Mr Snedden appeared as a witness in the war crimes trial of the late Serbian President Slobodan Milosevic.
"It is unusual in the sense that one won't necessarily determine the other. Snedden's request and circumstances are particular to his case, although no doubt the role that others play may be similar in nature and determination of those matters will assist in understanding what matters come before the court and how they'll be resolved," he told SBS.
