Police in Perenjori, approximately 350km north east of Perth, pulled the car over at 11pm on Friday night.
Four adults were travelling in the car’s seats, while two infant girls – both under 18 months of age – were discovered wrapped in blankets in the boot.
Sergeant Ross Gray said a portion of the boot had been removed so passengers could see the babies but they were completely unrestrained.
“We didn’t even see the second child to begin with because the first child was on top of her,” Sergeant Gray told PerthNow. “There was a load of shopping in the back and the girls were wrapped in a rug. It beggars belief.”
The driver, the girls’ grandfather, was fined $600 and eight demerit points.