Former New Zealand Warriors second rower Wairangi Koopu claims the abuse of prescription drugs occurred during his time with the club.
The Warriors stood down a group of players, including international trio Manu Vatuvei, Ben Matulino and Bodene Thompson, after it emerged they mixed prescription drugs with energy drinks on a night out.
Koopu said such substances were abused when he played for the club between 1999 and 2008, suggesting some players relied upon them too heavily.
"A few of the boys got hooked on prescription drugs. It wasn't necessarily to take them socially or recreationally, they were just there to help with anxiety levels, travelling, all sort of stuff," he said on Radio LIVE.
"Boys did end up relying on them a little bit too heavily sometimes.
"Every now and then the boys would have sleeping pills and then try to fight them to the death and not go to sleep. Of course that never ever worked; the boys just basically fell asleep.
"It was essentially abusing what they had, but sleeping pills aren't performance-enhancing."