A Minneapolis judge has described police body camera video of Australian life coach Justine Damond-Ruszczyk dying in an alley as so “visceral and shocking” most lay people would not be equipped to watch it.

The footage from four Minneapolis police officers, including Mohamed Noor who shot Ms Damond dead, has been cleared to be shown to the jury, members of the media and public during Noor’s murder trial.

The judge originally blocked media and the public, but an alliance of media organisations successfully argued the ban should be lifted.

“The footage on these BWCs (body worn cameras) shows the last moments of human life and the struggles of police and medical personnel to save that life,” Judge Kathryn Quaintance wrote in a memo filed in the case late on Wednesday.

“These moments are well outside the personal experience of most people.

“Most lay people are not well equipped to take in such visceral and shocking material.”

Noor, 33, has been charged with second-degree murder, third-degree murder and manslaughter for the July 15, 2017, shooting of Ms Damond at the entrance of an alley near her Minneapolis home.

He entered not guilty pleas.

After six days of jury selection the trial began in a downtown Minneapolis court on Tuesday.

Justine Damond was dressed only in her pyjamas when she was fatally shot. Photo: Linkedin

Ms Damond had called police to report she could hear a woman screaming and asking for help near her Minneapolis home.

It was just before midnight and when she approached the patrol vehicle driven by Officer Matthew Harrity and with Noor in the front passenger seat, Noor fired his gun and shot her in the stomach.

Noor’s lawyer has argued the officers were “spooked” and Noor shot in self-defence.

The judge, in her memo, offered insight into what the police video shows.

“Video from their BWCs establishes that Harrity and Noor were standing over the victim, where she lay in the alley, by 11:40:29pm, less than 15 seconds after the shot was fired,” the judge wrote.

“As depicted on the BWC, Harrity radioed ‘shots fired, one down’ and requested immediate emergency assistance.

“Harrity radioed that he had begun performing CPR on the victim at 11:41:39 and Noor took over CPR efforts about a minute later.
”… The recordings capture images of Harrity and Noor each administering CPR, their statements to the victim (who does not appear to be conscious), and her gasping for breath.”

The conversations between Noor and other officers captured on the video could prove crucial in the trial.

“Harrity’s BWC recording also captures an approximate twenty-second Q&A between Harrity and supervising sergeant after she had arrived on the scene,” the judge wrote.

Noor and Officer Harrity did not have their cameras on when the shot was fired.

Prosecutor Patrick Lofton told the jury on Tuesday that officers on the scene switched their body cameras on and off after the shooting.

“When body cameras go on there is a lot of silence,” Mr Lofton said.

The trial is expected to last three weeks.

-AAP