Two sisters were caught drink driving within hours of each other on opposite sides of Hamilton, police say.
A 24-year-old woman was nabbed driving while allegedly three times over the breath alcohol limit on Saturday evening in Frankton, Acting Sergeant Steve Jones says.
Later that evening police were called to the suburb of Enderley where they caught the woman's 22-year-old sister driving while allegedly twice over the breath alcohol limit.
She told officers she was the sober driver for a number of older relatives at the house.
The pair will appear in Hamilton District Court to face drink driving charges.
The older sister's boyfriend, a 31-year-old man, was also arrested at the Enderley house and charged with assaulting a security guard. He is due to appear in court next month.
"Older relatives were present when the two offenders were drinking and our message is that it isn't just the police's job to keep people safe, family members need to step up to the mark as well," Sgt Jones said.