A one-year-old toddler was tragically killed in Louisiana after his mother accidentally ran him over while reversing her vehicle out of her driveway.

Investigators described the event as a "tragic accident". Tralyn Crosby hit her young son Cai while reversing her SUV at their home in Larose, approximately 60 miles south-west of New Orleans, on Wednesday evening (3 January).

According to the local newspaper, Houma Today, police believe the 35-year-old was unaware her son had followed her outside the house once she got in the vehicle, while her husband and two other sons were inside the home at the time.

Lafourche Parish Sheriff Craig Webre says a 911 call came in at around 9:40pm on Wednesday, after a neighbour reported hearing screaming and crying outside.

Webre added the toddler was taken to Ochsner St. Anne Hospital in Raceland, where he was pronounced dead shortly afterwards. No charges will be pressed against Crosby, as investigators do not suspect impairment or foul play.

"This is a horrible tragedy for this family and the community," Webre said. "My heart goes out to the family, and I pray they can find peace in such a difficult time."

He added the community in Larose had rallied behind the Crosbys and showed tremendous support to the grieving family in the wake of the tragedy.