The three-year-old girl was taken to Queensland Children's Hospital with "significant head injuries" after the crash in Browns Plains, south of Brisbane, about 8.40am on April 18.

A woman was pushing a stroller while crossing Browns Plains Rd at the intersection with Webber Rd when it was struck by a light truck, a Queensland police spokesperson said.

The 28-year-old woman from Browns Plains was not physically injured.

The truck driver, a 43-year-old from Redbank Plains, was also not injured in the crash.

"Police are investigating after a traffic crash at Browns Plains earlier today," the spokesperson said.

"The toddler sustained critical injuries and was transported to the Queensland Children's Hospital."

Police are appealing for any witnesses or people with dash cam of the incident to contact Policelink online, or Crime Stoppers on 1800 333 000 or online at crimestoppersqld.com.au