Two young people who died in a fiery crash after careering off a bridge were members of Melbourne's illegal racing scene, and had been warned by their loved ones not to speed.

Harley Churchill and Ivana Clonaridis were travelling in Mr Churchill's ute at speeds of up to 160 km/h when the blue Holden Commodore left the EJ Whitten Bridge on the Western Ring Road at Keilor East and flew 100 metres through the air before exploding on the ground below.

It is unclear who was driving the ute, but police believe the driver had been racing the driver of a silver Ford before the accident, which occurred about 1.30am on Wednesday.

Earlier that morning, police had disrupted a gathering of 100 drivers doing burnouts and "wheelies" at an industrial estate in Campbellfield, about 18 kilometres from the crash site.

The ages of the pair have not been confirmed, but it is believed they both attended high school in Werribee. It is also understood both were P-plate drivers.

Ms Clonaridis' family declined to comment, while Mr Churchill's family could not be reached.

Mr Churchill's ex-girlfriend posted on social media that she had been shocked to wake to the devastating news.

Mr Churchill used a photo of his blue ute - which he described as "perfection" - as his profile picture on social media.

"I wish it wasn't true, harley i told you not to drive silly i always told you not to speed," she posted.

"Your so special to me and ill never forget you.

"Im just glad i got to spend my teenage years growing up by your side."

Ms Clonaridis's mother posted that she did not want her daughter to be with the "angels" because "I want her home, she was my angel".

A close friend described Ms Clonaridis as her "everything".

"Everyone loved you so much darling and will forever cherish the memories they shared with you.

"You brightened many lives and so many hearts are broken now."

The friend also knew Mr Churchill, writing that he "lightened every room [he] entered and all lives [he] ever crossed.

"Forever the funniest bloke."

Ms Clonaridis had only picked up a new car, a black Ford XR6 she described as "bae", two weeks ago.

The pair both had connections to individuals heavily involved in the street racing scene that thrives in Melbourne's north-west, with almost-weekly meets in industrial estates that are sometimes attended by as many as 500 people.

The events have been linked to two serious assaults in the past four months, including an all-female brawl at a McDonald's restaurant in Thomastown earlier this month, and the bashing of a police officer attempted to breath-test a driver in Campbellfield in September.

Police are searching for two people in a silver 2003-2004 Ford sedan with P-plates that are believed to have left the illegal street car event before racing Mr Churchill's car at the time of the accident

Detective Inspector Bernie Rankin said the high-speed crash was a desperately sad situation.

"It's a combination of things with young people," he said.

"They get in, spur each other on, encourage each other to do the next daredevil trick and this is the end consequence, which of course is the tragic end of the lives of two young people."