Thys, who holds the 15-year-old SA 42km record of 2:06:33, said on Tuesday he would compete for another seven months before hanging up his racing shoes.
“I have problems with high blood pressure, which has affected my performances over the last few years, but that’s not the reason I’m ending my career,” said the 42-year-old athlete.
“I’m tired of the way South African athletes are treated by the national federation, and I’m hoping as a politician I can make a difference.”
Thys said he would launch the party before the 2016 local elections in Prieska, where he was born and raised, in the Northern Cape.
A remarkable athlete, Thys remains among the top six in the SA all-time road running rankings over every distance from 10km to 42km.
He has been criticised for his bold approach to ultra-marathons in recent years, claiming he is capable of running under five hours at the Comrades Marathon but blowing out in his attempts to do so.
He was suspended after testing positive for Norandrosterone after winning the Seoul Marathon in 2006, but the decision was overturned in 2012 after a long-running court battle and he was exonerated.