Former Egyptian President Mohammed Morsi has been buried hours after he collapsed in court and died on Monday.

His lawyer told the AFP news agency the former leader had been buried in eastern Cairo early on Tuesday morning with his family present.

Morsi, who was 67, had been in custody since his removal from office in 2013.

Human rights groups, who had criticised the conditions in which he was kept, have called for an impartial investigation into his death.

His family and activists had repeatedly raised concerns about his health and the amount of time he was kept in solitary confinement, away from visits by lawyers and family.

His son, Abdullah Mohamed Morsi, told Reuters on Monday that Egyptian authorities had denied a family request for a public funeral in his hometown.