The Rome trial in absentia of four Egyptian security officials accused of torturing to death Italian student Giulio Regeni in 2016 can resume after a Constitutional Court ruling on Friday on issues raised by the defence.

The 28-year-old student's half-naked body was found in a ditch on the Cairo-Alexandria highway on February 3, 2016, a week after he disappeared on the Cairo metro on January 25.

Regeni, a Friuli-born Cambridge University doctoral researcher into Cairo street unions, was allegedly abducted and tortured to death by National Security General Tariq Sabir and his subordinates, Colonels Athar Kamel Mohamed Ibrahim and Helmi, and Major Magdi Ibrahim Abdelal Sharif.

The four have not attended any of the trial hearings so far after Egypt refused to notify them of the proceedings.

The Constitutional Court was called on to rule whether the Italian State should advance payment of the legal costs of the suspects.