Six-year-old Eitan, the sole survivor of a cable car accident near Lake Maggiore in Italy that shocked the world this year, must be returned to Italy by December 12, Israel’s Supreme Court has ruled.

In doing so, it rejected an application by the boy’s Israeli grandfather, who wanted to keep the child in Israel.

According to the decision, the man must also pay court costs, amounting to the equivalent of $US7,900 ($A11,066).

The boy, who lost both parents, his little brother and two great-grandparents in the May accident, had been flown to Israel secretly by his maternal grandfather in mid-September in defiance of a court order.

Since the accident, the boy had lived with his paternal aunt – Aya Biran-Nirko – in Pavia, Italy.

According to media reports, the public prosecutor’s office in Pavia has issued two international arrest warrants for the grandfather and an alleged accomplice.

In addition, the extradition of the two men has been requested.

The prosecution in the northern Italian city accuses the two men of strategically planning to take the boy back to Israel.

The accomplice was arrested in Cyprus on Thursday, according to media reports.

Eitan was born in Israel, according to media reports, but moved to Italy with his parents shortly after birth.

His aunt, Ms Biran-Nirko, had told the proceedings that Pavia in Lombardy was the boy’s home.

He was due to start school in Italy in September.

According to the reports, his mother’s family, who live in Israel, had argued that the parents had specifically planned to move back to Israel.

The boy should grow up in Israel, they said.

The question of custody must now be legally clarified in Italy.

-AAP