Ms Nkoana-Mashabane was an active member of the United Democratic Front (UDF) and served in the various structures of the Mass Democratic Movement (MDM) and the ANC underground structures in 1980s.
After the unbanning of the ANC in 1990, she served the party in various structures including the ANC Women's League and actively participated in the re-launch of the ANC Women's League in the country. She had served as a Chairperson of the ANC Women's League in Limpopo and she became a member of the National Working Committee (NWC) of the ANC Women's League from 1992 to 1995.
Ms Nkoana-Mashabane had been a member of Parliament in the National Assembly between 1994 and 1995; and later she was deployed in Diplomatic services and was appointed High Commissioner to Malaysia, servicing the Philippines and Brunei from 1995 to 1999.
She has also served as a High Commissioner to India, servicing Sri Lanka, Bangladesh, Maldives and Nepal from 1999 to 2005.
She had served as a member of the NEC and NWC of the ANC Women's League from 2004 to 2008; as a Deputy Secretary-General of the ANC in Limpopo from 2004 to 2008 and also as MEC for Local Government and Housing in Limpopo province in January 2005.