Judge Jorge Urso ruled that once Lukic, 38, has been tried at the
International Criminal Tribunal for the former Yugoslavia (ICTY) he could be sent on to Belgrade.
A legal source, who requested anonymity, said Lukic could be sent to The Hague before the end of January.
The former paramilitary leader had told Argentine authorities earlier that he feared for his life should he be sent back to Serbia rather than The Hague.
But judicial sources said he did not object to being extradited to Belgrade after his trial.
Lukic, one of the 10 most wanted Bosnian Serbs, was arrested in Buenos Aires on August 8, at the request of the ICTY, as he prepared to meet his wife and daughter who had just arrived from Paris.
The former paramilitary leader, who has been on the run for more than five years, has been accused of responsibility for the murder of some 150 Bosnian Muslims in the 1992-95 Bosnian war.
He faces 21 crimes against humanity charges and 12 war crimes charges for persecution, murder and inhumane acts.
According to the charges, Lukic allegedly set up a paramilitary group, the White Eagles that worked with police and military units between 1992 and 1994 to terrorise Muslim communities in Bosnia's Visegrad region.
In two separate incidents, the indictment says, Lukic and his group allegedly forced civilians into homes which they set ablaze, killing at least 140 people.
A Belgrade court has already sentenced him to 20 years in jail, in his absence, for war crimes, torture, kidnapping and murdering 16 Muslims in October 1992 in the Serbian town of Sjeverin. The 16 were passengers on a bus whose bodies were never found.
Lukic, who has insisted he is innocent, could be extradited by the end of the month, court sources said.
Lukic was the second war crimes suspect from the former Yugoslavia arrested in Argentina last year.
In May, authorities arrested Nebojsa Minic a former member of a Serbian paramilitary unit accused of ordering the rape, torture and murder of 12 people during the brief 1999 conflict in Kosovo.