Two children have been rushed to hospital in critical condition after being pulled from a backyard swimming pool in Sydney’s south-west.

Paramedics were called to a home on Lakewood Crescent in Casula just before 2:45pm today.

An 18-month-old girl and a 23-month-old boy were treated at the scene by paramedics.

One of the children was taken to Children’s Hospital at Westmead while the other was taken to Liverpool Hospital.

The child at Liverpool Hospital is now being transferred to Westmead.

Officers from Liverpool City Police Area Command have established a crime scene and commenced an investigation.

-with AAP