Petrac was arrested on an international warrant in Igoumenitsa on Wednesday for possession of a fake passport. He has been on the run since the abduction of General Vladimir Zagorec's teenage son in February 2004.
"The prosecution has requested five months in prison for the offence of possession of a fake passport," the head of the press office of the Greek Ministry for the Merchant Navy, Panatiotis Skalkos, told Hina by telephone.
Skalkos added that Petrac had also been fined 1,500 euros for the same offence. He, however, noted that a convicted person need not spend the given time in jail provided that he pays 4.4 euros a day and remains in Greece.
Asked if Petrac could appeal the court judgement, Skalkos replied that he could not say.
Skalkos said that the request by Croatian authorities for Petrac's extradition had not been dealt with yet.
The Zagreb County Court has described Petrac as the mastermind of the abduction of General Zagorec's son and sentenced him in absence to six years' imprisonment.
Petrac is also seen as a very important link in a network of supporters of fugitive Croatian army general Ante Gotovina, who is wanted by the UN war crimes tribunal in The Hague.
The Croatian Ministry of Justice told Hina on Friday it had learned about the judgement handed down by the Greek court, but that it had not yet been officially notified.
The Ministry of Foreign Affairs did not have any information about the court ruling on Friday afternoon.
The head of the Justice Ministry's International Legal Aid Department, Melanija Grgic, told Hina that the court judgement against Petrac for his illegal entry into Greece should not affect his extradition to Croatia, because Croatia's request for his extradition is a separate matter.
She added, however, that if the court orders Petrac to serve his sentence in Greece his extradition might be delayed.
"The extradition process is a separate matter which does not depend on the trial for the illegal entry into Greece. But his extradition might be delayed over the service of the sentence even if the request for Petrac's extradition is granted," Grgic said.
She added that her ministry had learned of the Greek court's decision but that it had not yet received official notification.
Petrac's Greek lawyer Alexis Kougias has announced the possibility of Petrac seeking political asylum in Greece, saying that the international warrant for the arrest of his client is based on trumped-up charges.
Croatian Radio quoted Kougias as saying on Friday that his client would not appeal the Greek court's ruling.
The radio said that a court hearing on Petrac's extradition to Croatia was due to take place on the island of Corfu in two weeks.