She took her father back two months later because the lesion had grown to twice the size and begun to bleed.
Ms Du said Kong referred them to a diabetes clinic, where a doctor told them the problem was not because of diabetes.
She said Kong gave them a referral for blood tests. Two days later, he told her Mr Du had a melanoma.
Mr Du had surgery for the melanoma but died on January 20, 2007, after going into a coma.
Prosecutor Anna Longdill said Mr Du's family had laid a complaint about Kong with the Health and Disability Commissioner, which was dismissed.
She said Kong had changed his notes to say he had offered to refer Mr Du for a biopsy but the family were not prepared to spend the $20.
"The only rational explanation, on the Crown's case, is that Dr Kong ... wanted to stop the commissioner in his tracks and put this one to bed. Indeed, he succeeded."
Kong's lawyer, Marc Corlett, said his client did not deny changing Mr Du's records but the alterations were made after he talked to his nurse and wife, Wendy, who had also examined Mr Du.