Mpumalanga police are looking for the driver of the vehicle involved in the crash in which provincial government spokesperson Joseph Mabuza was killed.
"The unknown driver simply disappeared from the crime scene before authorities could arrive," Brigadier Leonard Hlathi said on Monday.
Mabuza is understood to have been hit while doing a U-turn as he travelled on a motorbike along the N4, near Hectorspruit in Mpumalanga on Sunday.
The town is close to Komatipoort and near the busy Lebombo border post with Mozambique.
Mabuza, the head of communications in the Mpumalanga Community Safety Department, died at the scene.
READ: Mpumalanga safety and security MEC's spokesperson killed in crash
Police consider the driver of the vehicle as a "fugitive" and have asked for information on the driver's whereabouts to be relayed to Constable Vusimuzi Thobela on 072 196 8225, or Crime Stop on 08600 10111.
Mpumalanga's police commissioner, Lieutenant General Mondli Zuma, appealed to drivers to exercise restraint and be patient with one another.
He said it was a crime to leave a crash scene before law enforcement and emergency services officials arrived.
Zuma also extended condolences to the Mabuza family, his friends and his colleagues.
The communications team of the Department of International Relations and Cooperation, led by its spokesperson Ndivhuwo Mabaya, also issued a statement offering condolences.
"Mabuza was a colleague, an excellent communicator and a friend to many of us. His death is painful and should remind us of our responsibility on the road, and the growing number of South Africans who lost their lives during this holiday season."
Mabaya said Mabuza always reminded them of their responsibility on the road.
"I do hope that law enforcement officers in Mpumalanga and across the country will be inspired by the energy and commitment of Mabuza to road safety and be more vigilant and harsh on those who break the laws and rules of the road."
ANC head of the presidency Zizi Kodwa also offered condolences via a tweet.
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