Car ploughs into pedestrians, six hurt

Three people have critical head injuries after a car mounted the kerb and hit pedestrians at Penrith in Sydney's west.

The Ambulance Service says it was called to the real estate agent on High Street about noon, where a car had smashed into the front window.

Paramedics have treated six people and taken five to Nepean Hospital.

Two men and an elderly woman have critical head injuries while a baby boy has minor leg injuries.

The real estate agency's owner, Michael Ball, says he was going into his office when it happened.

"I could just hear the car flying down the street," he said.

"Basically, I saw her come up onto the gutter and take the people out. I jumped out of the way and there were people pushed, you know, down the street and yeah it was terrible."