Robert Ralston was critically injured on March 29 after falling from a trailer police say was towed by Andrew Mercer, according to court documents.
Mr Ralston died in hospital yesterday morning.
At the time of the incident, Senior Sergeant Anthony Bond, of Dunedin, said police were called to Brockville Rd at 4.30pm.
Police said the pair had been arguing.
Mercer was said to have got into his car, which had a trailer attached, Snr Sgt Bond said.
Mr Ralston got on to the trailer but fell off when the car accelerated suddenly.
He hit his head on the ground, suffering serious injuries and was rushed to hospital by Hato Hone St John in a critical condition.
In a statement yesterday, police said Mercer was due to appear in the Dunedin District Court on April 24, charged with reckless driving causing injury.
Further charges were being considered.
