The St George Illawarra Dragons doctor was denied the chance to review vision of Josh Dugan's collision with teammate Russell Packer - which led to the joint venture club being slapped with a staggering $100,000 fine over a concussion breach - because a sideline television was not working at the time.

Fairfax Media understands Dragons medico Dr Tom Carrigan was unable to assess Dugan for any symptoms of concussion on a monitor from inside the Head Injury Assessment tent because of a technical glitch.

The Dragons were trialling a new communications system on behalf of the NRL on the night, and Carrigan was able to talk to head trainer Nathan Pickworth, who conducted the on-field assessment of Dugan.

The broadcast frequency on the system is encrypted to prevent eavesdropping.