An Australian mum has been ordered by the police to pay a fine of $650 as she was caught over speeding at 127km/h along with an unrestrained child passenger at the back of her car.

The woman was travelling on Indian Ocean Drive from Geraldton to Perth between Leeman and Jurien Bay on Friday morning.

The woman said she had travelled that distance to pick up a friend and her child, according to Sergeant Mark Cannon.

When accosted, police saw an 11-month-old boy who was unrestrained and just sitting on his mother's lap at the car's back seat.

"If the car had crashed, the child would have been crushed," Cannon said.

There was another child seated in the front passenger seat, but was properly restrained.

Apart from the combined fine, the woman was also slapped with a loss of six demerit points.

Speeding and reckless driving are considered as one of the major causes of road and car accidents. Exceeding the posted speed limit for the zone a person is driving in/through is classified as speeding. The faster one goes, the harder it is to stop. Speed limits are imposed for safety reasons especially in school zones and busy pedestrian areas. Reckless driving is willfully disregarding traffic regulations and exhibiting aggressive driving tactics such as changing lanes without signaling.

Car accidents can happen anytime, anywhere. Remember that every time you sit behind the steering wheel, you hold the responsibility of yourself and those around you in your hands.