It is alleged 0.43g of methamphetamine was inside.
William's lawyer Poppy Eunike says her client is not objecting to the indictment and admits to having drugs on her when she arrived in Bali.
"She admits that she carried it. It was given to her by a friend," Ms Eunike told NZ Newswire after the court appearance.
She said William, who is believed to have been living in Melbourne when she flew to Bali, was using while in Australia and therefore should be eligible for a lesser sentence.
The 27-year-old from New Zealand was "nervous", Ms Eunike said.
The maximum penalty for the possession of less than 5g of drugs carries a 12-years prison sentence, while importation has a maximum of 15 years.
If she is convicted for drug use, however, she would face a maximum of four years in prison.
William is due to return to court on January 31.