Police are alleging that the 51-year-old slowly poisoned her 18-year-old daughter and 26-year-old son over an 'extended period'.
The deaths occurred between September 2012 and July 2017, police confirm.
The daughter is believed to have been found dead at a home in Maudsland, Queensland, while her brother's body was discovered at the same address nearly five years later.
The woman has been taken into custody and will face Brisbane Magistrates Court on Wednesday.
Law enforcement officials are due to release more information at a media conference in the coming days.
This article originally appeared on New Idea