Brisbane boss Bruno Cullen on Monday hit out at allegations the Broncos were covering up a drugs issue involving one of their high profile players, Cullen threatening legal action over what he claimed were ''scurrilous'' accusations.

Gallop said the NRL had no evidence of any Broncos player testing positive to drugs, but warned of dire consequences should Brisbane or any other club attempt to cover up positive tests.

''Clearly, like anything else, if there are lies being told then the consequences may be more severe,'' Gallop said.

''The Broncos have obviously come out fairly emphatically about some of the allegations.

''From our point of view it's important that the policies are adhered to and the policies are ones that provide not only for random testing but also for targeted testing.

''We don't go into where we are up to in relation to those things unless we get results which lead to us disclosing it under the policy.''

The player with the alleged drug problem was not named publicly in Monday's Daily Telegraph report, but Cullen said the player in question had been tested a number of times over a long period with the club.

Gallop said unsubstantiated allegations had the ability to harm the reputation of the club and players. AAP