V8 Supercars veteran Craig Lowndes and rival Holden co-driver Warren Luff have been involved in a heavy crash during practice for Sunday’s Bathurst 1000.

The brakes on Luff’s No.2 Holden Racing Team Commodore appeared to fail as he entered turn two on the Mount Panorama circuit in Saturday morning’s session – throwing the car sideways, into the tyre barrier and onto its roof.

Luff clipped Lowndes’ Red Bull Racing Commodore on the way, sending the veteran into the concrete wall and destroying the rear of the car.

Both emerged from their cars and gave each other a hug.

They are being assessed by doctors.