Controversial biochemist Stephen Dank has been banned by the NRL over his involvement in Cronulla’s 2011 supplements program.

NRL boss Dave Smith confirmed on Saturday that Dank would never again be permitted to practise in the competition.

The announcement on Dank came as Smith also confirmed that 12 past and current Shark’s players will serve a 12-month backdated suspension for breaches of the game’s anti-doping rules.