Bathurst 1000 organisers have cancelled the Top 10 Shootout for the first time in 44 years due to heavy rainfall at Mount Panorama.

The session — which was to decide the top-10 grid positions for Sunday's race — was scheduled to start at 5:05pm AEDT.

Motorsport Australia officials spent over an hour deliberating whether to let the top 10 drivers from Friday's first qualifying session take to the track to decide their starting order for Sunday's race.

But it was deemed unsafe after the final Super2 and Toyota 86 series races were also canned, with rivers of water running on the track at times.

"Race Control has advised that the Supercars Top 10 Shootout has been cancelled due to extreme weather, leaving the track in an unsafe condition for competition," a Motorsport Australia statement read.

Cam Waters will start from pole for the second time, having also secured the spot in 2020.

Waters said he was disappointed to see the shootout cancelled but preferred to see the full field out for Sunday's race, rather than have cars wrecked in the hazardous conditions.

"The rain was crazy and you saw the rivers and everything going on. It was going to be a bit of a safety thing," he told Fox Sports.