The former governor of Córdoba province, José Manuel de la Sota, died on Saturday night when the vehicle he was driving crashed into the rear of a truck on a road connecting Córdoba capital with the city of Río Cuarto.
The car crash is being investigated by Córdoba police, with suspicions de la Sota was driving well over the speed limit of 130 kilometres per hour.
The accident happened at around 8pm on Saturday evening on Route 36 between Córdoba capital and Río Cuarto. The driver of the truck, a 35-year-old man, is "stable" in hospital, local authorities reported.
Dissident Peronist Sergio Massa and members of the Renewal Front movement he leads attended the event en masse to honour de la Sota, a stalwart of the Peronist movement who had long supported Massa's political ambitions.
Rumours circulated on Sunday that de la Sota himself had planned to run for president in 2019 against Mauricio Macri.
In a career spending more than 40 years, de la Sota had been governor of Córdoba province, ambassador to Brazil, and a national Senator and lawmaker for his province.
Political figures across the aisle paid tribute to de la Sota, after news of his death became public.
"Shocked by the death of the former governor of Córdoba José Manuel de la Sota in a tragic car accident. My condolences to his entire family," President Mauricio Macri said in a message posted on social networks.