The X Factor judge, who wed McMahon's actor son Julian in 1994, said that she was not welcome in the family home during their brief marriage.
Minogue wrote in her autobiography: "I was never once allowed to visit the McMahon family house in Sydney. I had to sit in the car and wait for Julian while he visited his mother. She wanted nothing to do with me. I simply wasn't good enough."
Nip/Tuck star Julian's father was former Australian Prime Minister Sir William McMahon.