A 33-year-old Huntingdale woman failed a preliminary breath test in Gosnells on Tuesday night.
She had two children aged 18 months and six weeks old in the car with her.
At about 7.20pm Regional Operations Group officers were on patrol when they saw a white Ford Territory being driven on Corfield Street.
It has been alleged the woman driving the car appeared to have trouble controlling it with officers allegedly observing the car drift out of its lane.
Police stopped the car on Igran Crescent and following the failed breath test a family member was called to the scene to pick up the two children.
The woman was taken to Gosnells Police Station for a second evidentiary breath test and it will be alleged she failed it with a record reading just over 0.1 per cent.
She will be charged by summons.
