"It is important to have good information, and to help us understand the issue better, we are surveying our extensive network of rugby and medical contacts to capture their experiences and knowledge of this type of abuse."
The issue was recently brought to light when it was found a handful of Kiwis players, reportedly including Sonny Bill Williams and Kieran Foran, mixed sleeping pills and energy drinks during last year's World Cup. The effect is said to be similar to some recreational drugs but is not banned under the Wada code.
Former NZ under-20s rugby prop Tukiterangi Jahna Raimona appeared in the Invercargill District Court recently when he admitted stealing a team doctor's pad and trying to obtain 160 prescription pills.
NZRL high-performance manager Tony Iro said it will do its own testing for prescription drugs if it suspects a player has misused them and also expects Australian testers to take samples from the team around this year's Anzac test in Sydney on May 5. "If we suspect anything, we have the right to test when we want and for what we want," Iro said.
"The use of those substances isn't conducive to what we consider peak performance and we would hand down appropriate penalties if any players tested positive.
"We saw the impact and effects of it [during the World Cup]. The NRL has moved pretty quickly to have the testing introduced this season and I think it's a good move all round."
The NZRL has also amended its code of conduct, which must be signed by all players, and it received the support of the senior playing group.
Anecdotal evidence suggests the use of sleeping pills has been widespread in a number of sports for some time as players look for a way to get around alcohol and drug policies. It's not illegal and, previously, didn't contravene any anti-doping policies but the NZRL holds genuine concerns a player might not wake up after misusing sleeping pills.
The NRL will now expand its testing of urine samples to include one for illicit drugs for two classes of prescription drugs - Benzodiazepines (which includes Valium, Serepax, Mogadon and Rohypnol) and Zolpidems (which includes Stilnox, Zolsan and Stilnoct).
"We will know if prescription drugs are being abused in our game and we can take steps to remedy the problem," said NRL chief operating officer Jim Doyle. "If there is a problem the NRL may decide to impose sanctions for the abuse of prescription drugs from 2015."