Nine South African policemen have pleaded not guilty to charges of murdering a taxi driver who was handcuffed and dragged behind a police vehicle.

A post-mortem report circulating in the courtroom in Benoni, east of Johannesburg, said Mido Macia, 27, died of oxygen starvation.

He also suffered a range of injuries including "extensive abrasions on the face, limbs and body" and bruises to his back, torso and testicles.

Mobile phone footage of the incident taken by a bystander showed Mr Macia, who was from Mozambique, scuffling with police after parking his vehicle illegally.

He is then subdued and handcuffed to the back of a police truck before the vehicle drives off in front of scores of witnesses.

He died later in a police cell.

The driver of the truck, Lungisa Edwaba, told the court he had not known Mr Macia was cuffed to the back of the vehicle and had only driven off because someone in the crowd had thrown something at him.

The images, which were broadcast around the world, rekindled memories of apartheid-era police abuses and highlighted the alarmingly high number of people who die in police custody in Africa's largest economy.

According to the Independent Police Investigative Directorate, the police's main watchdog, nearly 1,000 people died last year in police custody or as a result of police action.

Police commissioner Riah Phiyega blamed Mr Macia's killing on a few bad apples in a massive force.