Queensland stewards have stood down jockeys Amy Graham and Casey Waddell as they investigate videos, published online, that showed them in the presence of a white powder substance.
Racenet has seen the two separate videos, which run for a combined total of 11 seconds.
The first video goes for five seconds and shows Graham, 28, snorting a white powder substance from a saucer while leaning over a kitchen bench, with music playing in the background.