The family of a woman recovering in intensive care say that her car was hit by a police officer travelling at 140km/h with no sirens.
Gai Vieira, 68, was driving her Mercedes-Benz in Cronulla on Wednesday when it collided with a police car at the intersection of The Kingsway and Connels Road.
The crash has left Mrs Vieira in St George Hospital's intensive care unit, where she is now recovering.
Her two-year-old grandson was also in the car, but was unhurt.
Mrs Vieira is the wife of Sydney racing identity Bert Vieira.
The owner-breeder's horse Trapeze Artist is set to run at Rosehill Gardens on Saturday in the lead-up to The Everest next month.
Police on Thursday said that the officer, who suffered minor facial injuries, was pursuing a motorist he had seen using his mobile phone behind the wheel.
Mrs Vieira's son on Friday appealed for witnesses to the crash in a Facebook post.
"We have been told allegedly the police officer that hit her was travelling approx 140km/h without his sirens on and didn't have a chance to use his brakes at all," her son Trent Vieira wrote.
"We are appealing for any witnesses ... to please make contact."
In a press conference on Thursday, Assistant Commissioner Michael Corboy would not comment on whether the patrol car had its lights and sirens going.
"That highway patrol car was in the process of locating that car and speaking to the driver about their use of a mobile phone," Assistant Commissioner Corboy said.
"That hadn’t happened when the collision occurred."
The crash is now being investigated as a critical incident.
"We have a number of people who have spoken with us already and we’ve received a number of different versions of the crash. We’re going through this meticulously. We have very experienced crash investigators looking at this," Assistant Commissioner Corboy said.
We’re going through this meticulously.Assistant Commissioner Michael Corboy
Investigators are hoping to complete their inquiries as quickly as possible, he said.
"This is a tragic incident ... during an operation, the last thing we want to do is be involved in a crash with a member of the public and our thoughts are with the family at this stage."