NSWRL officials contacted police after drugs were discovered in a dressing room at Saturday's match between North Sydney Bears and Wyong Kangaroos.

However, there may be an innocent explanation as it emerged after Fairfax Media published a story about the discovery that paramedics attending an earlier NRL Under-20s match at North Sydney Oval had misplaced a package.

An NSWRL ground manager found the drugs after the Intrust Super Premiership match at North Sydney Oval and the reported the discovery on Monday.

The police were immediately notified and are investigating the source of the drugs.

However, NSWRL officials are confident the drugs do not belong to any of the players involved in the match, which was won 30-4 by Wyong, a feeder team to Sydney Roosters. The Bears are the feeder team for South Sydney in the NSW Cup.