Joseph Helu of the Otara Tongan Methodist Church, said Ms Liku had been on her way to clean the church, as she was understood to have done every Wednesday.
Local media reported that her brother, who was a pastor at the church on Ormiston Rd, came across the crash scene.
Reverend Vaikoloa Kilikiti was reportedly on his way to the church when he recognised his sister's damaged Mitsubishi Pajero.
Ormiston Rd resident Tetini Vaeteru said he saw a person under the 4WD and the driver sitting motionless in the front seat after the crash.
The front passenger door of the 4WD was badly damaged, as was the bonnet of the police car.
A power pole was also knocked over in the crash.
Counties Manukau district commander John Tims told the press conference an independent investigator from another region would be brought in to probe the crash.
"This incident is every police officer's worst nightmare. Our staff come to work every day to keep our communities safe. We never want something like this to happen."
The police officer involved in the crash had been on his way to a house robbery where the offenders were still there.
His car's lights and sirens were on at the time.
Mr Tims would not be drawn at how fast the police car would have been travelling when the crash happened, but said there was strict protocols for attending priority one incidents.
"Police are committed to finding out what occurred this morning,'' he said.
He said the Police's thoughts were with the family of the dead woman.
The police officer involved in the crash was "distressed and shocked" and would be taking some time off to recover, Mr Tims said.
Counties Manukau Police have urged anyone who witnessed the crash to call 09 261 1300 immediately.