The October 16 car crash was between 31-year-old's Mercedes AMG and a Mitsubishi Outlander.
Following the collision, Mr Mehajer was treated by paramedics and transported via ambulance to Westmead Hospital at the time.
While the property developer's lawyer Brett Galloway revealed his client had been a passenger in the car that crashed, footage by several TV cameras at the scene depicted Mehajer being taken out from the driver's seat of the Mercedes SUV.
And now, according to ABC News, NSW detectives arrested Mr Mehajer at his Vaucluse residence.
Authorities told the website that Mehajer was arrested this morning along with two other men, aged 28 and 30, and a 31-year-old woman.
This is a developing story.