IT HAS been alleged the police officer behind the wheel of a highway patrol car that slammed into a Mercedes in Cronulla on Wednesday was driving at approximately 140km/h, without its sirens on.

The driver of the Mercedes, Gai Vieira, 68, who is the wife of prominent racehorse owner Bert Vieira, is currently in ICU fighting for life following the accident at the intersection of The Kingsway and Connels Rd.

It is understood Ms Vieira was turning right out of Connels Rd onto Kingsway and the police car was travelling west on Kingsway before the collision. Her two-year-old grandson was also in the car but escaped with minor injuries.

The senior constable, who was travelling alone, was trying to pull over a driver who was using a mobile phone before the crash, but there are conflicting reports of what happened.

In a desperate plea to understand the circumstances of the accident, Ms Vieira’s son Trent took to social media pleading with anyone who has information to come forward.

In a Facebook post he also wrote: “We have been told allegedly the police officer that hit her was travelling at approx. ‘140km’ without his sirens on and didn’t have a chance to use his brakes at all.

“We are appealing for any witnesses of the accident to please make contact with me. We would greatly appreciate your support as we seek to understand what happened.”

In a press conference yesterday, NSW Police Assistant Commissioner Michael Corboy said police had received a number of different eyewitness accounts of the crash.

Mr Corboy would not say if the police car’s lights and sirens were activated, but said: “We’ll be taking action if required.”

An independent investigation has been launched and will look into the speed of the police vehicle, if its lights and sirens were activated and the actions of the Mercedes.

He did confirm that the police officer had just received information that a nearby driver was using a mobile phone in the moments before the collision.

“We do have to catch up to vehicles, but the use of lights and sirens is something that is normally associated with this,” Mr Corboy said.

“We will confirm that in coming days.

“We have to be fair to everyone involved and we have to speak to everyone involved and we need that information to make those statements.”

However, a witness who spoke to The Daily Telegraph claims to have “heard the sirens and saw the lights as well”.

Another witness said he saw Ms Vieira lying near the car after the crash.

“The woman was turning right out of Connels Rd onto the Kingsway and she was hit by the police,” the man said.

Ms Vieira’s grandson and the police officer were both taken to St George Hospital but have since been discharged. The police officer was treated for minor facial injuries.

Mrs Vieira’s husband Bert is a part owner and breeder in horse Trapeze Artist, which is tipped to take out The Everest race — the world’s richest turf race at $13 million — at Randwick in October.

However, a decision on whether the horse runs at Rosehill Gardens tomorrow — a crucial lead-up to the major race, rests with Mr Vieira.

Trapeze Artist is entered for the Group 2 $200,000 Theo Marks Stakes (1300m).

“It is entirely up to Bert; if he wants Trapeze Artist to run, we will run,’’ trainer Gerald Ryan told The Daily Telegraph.

“But if he doesn’t want it to run because of what has happened we will scratch and go to Plan B.’’

Trapeze Artist, the early favourite at $4.50 for The Everest, is also at the top of betting at $2.80 for the Theo Marks Stakes.

Ryan was shocked to learn of the car accident which has left Vieira’s wife, Gai, in a critical condition in St George Hospital, the publication reported.

As a mark of respect, the trainer scratched one of the owner’s horses, Fast Train, from a race at Gosford yesterday.

Anyone with information about this incident is urged to contact Crime Stoppers on 1800 333 000.