A 16-year-old boy has been charged with murder after allegedly fatally stabbing his mother and seriously injuring his sister.

The teenager was charged on Wednesday with one count of murder and one count of attempting to unlawfully kill after police went to a home at Bentley, in Perth’s south-east, on Tuesday morning.

When officers arrived at the family home, they found the 35-year-old mother dead.

The 12-year-old girl was also stabbed but managed to flee the house, making it to a nearby highway for help.

Bystanders gave the girl life-saving first aid and she was taken by ambulance to Perth Children’s Hospital. She remained in a critical but stable condition on Wednesday.

WA Police Acting Inspector Jessica Securo said the incident had shocked the community.

“This incident will have a significant impact on the family, friends and loved ones of all those involved,” she said.

“Our thoughts are with them all, particularly the 12-year-old girl.”

The 16-year-old is due to appear before the Perth Children’s Court on Wednesday.

-AAP