“Not even her death can erase it,” Mthethwa said in a statement.
He joined President Jacob Zuma and Archbishop Desmond Tutu in extending condolences to her family and friends.
“Nadine Gordimer was a daughter of the soil and was a courageous supporter for the liberation of our country and continued to speak for the voiceless right until the end,” Mthethwa said in a statement.
“May her soul rest in peace.”
In a statement sent on behalf of the Gordimer family, law firm Edward Nathan Sonnenbergs said Gordimer died peacefully in her sleep at her Johannesburg home on Sunday.
“Her son Hugo and daughter Oriane and her caring helpers were with her… A private memorial service will be announced at a later date,” said the law firm.
Gordimer was 90 years old.