ANC Chief Whip Stone Sizani has extended his party's condolences to the family of UDM deputy president Ntopile Kganyago, who died on Wednesday.
"We are shocked at the death of such an experienced politician, a servant of the people and a well-versed legislator," his office said in a statement on Thursday.
While the African National Congress had not always agreed with Kganyago, who served as a United Democratic Movement MP from 2004, it had "never doubted his devotion to our constitutional democracy and his commitment to the success of this country and her people".
It was for this reason that the ANC had invited him to serve as public works deputy minister, a post he filled from 2004 to 2009.
"We extend our heartfelt condolences to his wife, children, friends and colleagues in the UDM. We wish his family courage and strength during their difficult period of mourning."
According to reports, Kganyago died of a short illness at a hospital in Centurion, Pretoria, on Wednesday night.