Queensland Police are also reeling from the tragedy that occurred in Cairns on Thursday, sparking a major crash probe and corruption watchdog oversight.
The Trinity Beach woman was struck about 6.55am as the police vehicle turned at the intersection of Sheridan and Lee streets in Cairns' north, police said.
Three officers - one sergeant and two senior constables - were in the 4WD when it hit the woman.
They immediately called for help and tried to save the woman, fighting to keep her alive on the roadside.
Paramedics rushed her to Cairns Hospital with life-threatening injuries where she later died.
Regional Operations Deputy Commissioner John Tims said the tragedy had "changed the life of a family forever".
He said the "incredibly sad loss" was also being deeply felt across the state police service.
"No police officer shows up to work expecting to be involved in a situation like this," he told reporters in Brisbane.
The busy intersection was locked down as detectives and crash investigators moved in, with the officers involved taken away from the scene.
A Forensic Crash Unit investigation is under way, led by Ethical Standards Command with oversight from the Crime and Corruption Commission and the coroner, in a bid to piece together exactly how the collision happened.
Deputy Commissioner Tims said he could give "100 per cent assurance" the investigation would be thorough.
Standard testing of the officers will form part of the probe, which will examine what happened before and during the crash and consider any future safety recommendations.
Police said support was being offered to the woman's devastated family, as well as the officers and first responders involved in the incident.
Motorists have been urged to avoid the area while part of the street remains closed.
Witnesses - including anyone with dash-cam footage - are being urged to come forward to help investigators understand the woman's final moments.
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