Children who aren't big enough for a seat belt, may soon be required to sit in a booster seat when in a car, new legislation in Manitoba says.

The mandatory booster seat law would apply to children under 145 cm in height or 36 kg in weight.

In non-metric terms, the law would apply to children shorter than 4 feet 9 inches tall or lighter than 80 pounds.

According to the province, car crashes are among the leading cause of injury and death among booster seat aged children.

Dr. Lynne Ward told CBC News that many children do not fit well under a regular seatbelt.

She added that, in a crash, a regular seat belt could even hurt a child who is too small for it.

"They can be fatal," Ward said. "We've had fatal injuries and the spinal cord injuries. Its so devastating. I mean, you've got a kid [and] tomorrow they're in a wheelchair."

If the legislation passes, the mandatory booster seats law could go into effect as early as June.