Five years after the fatal police shooting of 29-year-old Yamatji woman JC in Geraldton, an inquest into her death began on Monday.

In 2019, First Class Constable Brent Wyndham shot and killed JC while she was holding a knife and scissors during a mental health crisis.

He was charged with murder but was acquitted of murder and manslaughter in a 2021 trial, sparking national outcry and protests.

Eight officers responded to calls about JC carrying a knife.

"Your Honour will hear from each of those eight officers involved," counsel assisting Rachael Young told the court.

"Each gives evidence of giving, or hearing the giving, of commands to JC to drop the knife, of threats that she will be tasered, of using her first name... to try and get her to drop the knife. JC did not comply with those commands.

"At 1819 hours and 39 seconds, Officer Cleghorn radioed again," Ms Young said.

She quoted: "it is [JC, using her first name] and she's ignoring us she's got a pair of scissors in her left hand ... and she's got a really big knife in her right hand. We're still in the vehicle, she's not acknowledging our direction."

In both those radio calls, a male voice, believed to be Officer Walker can be heard yelling out 'Oi', presumably to JC.

JC continued walking down Petchell Street. Moments later, she was shot dead.

Sen. Const. Walker had ordered JC to "drop the knife" before additional officers arrived.

State Coroner Ros Fogliani asked Walker if shouting "oi" had escalated the situation or provoked JC.

Walker responded that he believed it had de-escalated the situation by gaining her attention.

He disagreed with the notion that JC might have felt surrounded or terrified before being shot.

When it was suggested to Sen. Const. Walker that JC was not moving, making threats, or raising her weapon when shot, he conceded there was no immediate threat to police.

"She was a risk to people but not an imminent threat," he said.

Walker added that the situation might have been different if former police officer Adrian Barker had not approached JC so closely.

The inquest will also examine the adequacy of JC's medical care, considering she had schizophrenia and had been hospitalised days before her death.

JC had expressed suicidal intentions and was found by police walking with a knife and scissors shortly before the shooting.

The inquest is expected to last two weeks and will be held in both Geraldton and Perth.