Perry Kouroumblis landed in Melbourne late on Tuesday night after being extradited from Italy, marking the first time in about eight years he has set foot on Australian soil.
It is expected he will be interviewed by police on Wednesday and subsequently face Melbourne Magistrates Court.
Kouroumblis will formally be charged with two counts of murder and one count of rape during the court appearance.
He was arrested at Rome's Leonardo Da Vinci Airport in September over the alleged slaying of Suzanne Armstrong, 28, and Susan Bartlett, 27, in January 1977.
Suzanne Armstrong (right) and Susan Bartlett were murdered in in 1977. (HANDOUT/VIC POLICE)
Dubbed the "Easey Street murders", the friends were found dead with more than two dozen stab wounds in their home on Easey Street in Collingwood in Melbourne's inner north.
Ms Bartlett's 16-month-old son Gregory was found unharmed in his cot.
The 65-year-old Kouroumblis was filmed sporting a white beard and wavy grey hair as he flew back to Melbourne on a Qatar Airways flight flanked by Victoria Police officers late on Tuesday.
Police had issued an INTERPOL red notice alert for Kouroumblis on two charges of murder and one of rape.
The Greek-Australian dual national was not able to be arrested in Greece due to a 20-year statute of limitation on the initiation of murder charges.
Following his arrest, he told Italian authorities he was "happy" to be extradited and his lawyer said he was prepared to face trial but that a judge will have final sign off.
Kouroumblis maintains his innocence.
Perry Kouroumblis is expected to face two charges of murder and one count of rape. (Stefan Postles/AAP PHOTOS)
Ms Armstrong and Ms Bartlett were last seen alive on January 10, 1977, and their bodies were found three days later.
Victoria Police Chief Commissioner Shane Patton has described the murders as "an absolutely gruesome, horrific, frenzied homicide".
He said advances in technology, investigative techniques and retracing statements had contributed to the breakthrough in Victoria's "most serious cold case and longest cold case" ever solved.
"There is simply no expiry date on crimes that are as brutal as this," he said.
The force offered a $1 million reward in 2017 to catch those responsible.
The women went to school together at Benalla in Victoria's north and their families said their deaths changed many lives irrevocably.
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