Senior Rebels biker Nick Martin has been shot dead in front of bystanders at Perth Motorplex.

Digital StaffAAP/7NEWS

Senior Rebels bikie Nick Martin has been shot dead in front of bystanders at Perth Motorplex.

The 50-year-old was reportedly gunned down in front of crowds, including families and children, at the Kwinana Beach drag racing venue about 8.30pm on Saturday.

Martin and another person were treated by paramedics at the scene, but he couldn’t be revived.

The other victim was transported to hospital.

A senior Rebels bikie was gunned down in front of innocent bystanders at Perth Motorplex on Saturday night. Credit: 7NEWS

One spectator told The Sunday Times the shooting had occurred just metres from the track, while another woman said her children had been forced to witness the aftermath as police would not let anyone leave.

“While we were waiting to leave we could see an ambulance officer do CPR on a body lying on the ground. My kids could see everything and they are still very shaken about this,” she said.

The death comes just weeks after Martin was assaulted at a Scarborough bar by a Hells Angels enforcer, as reported by The West Australian.