Reds captain James Horwill was $2500 for his outburst against the "stupid refereeing decision".

Contrite Queensland captain James Horwill has been fined $2500 for his outburst against the "stupid refereeing decision" that sank the Reds in their last Super Rugby match.

Horwill pleaded guilty to misconduct and offered to apologise to match officials for complaining his side was "robbed by a stupid refereeing decision" in their three-point defeat to the Melbourne Rebels.

The Wallabies lock was fuming that television match official Steve Lescynscki prompted referee Steve Walsh to overturn a late penalty for an alleged eye gouge by Reds forward Ed O'Donoghue.

O'Donoghue was later cleared by governing SANZAR in little solace to Horwill and the Reds, who lost the game 30-27 from the resulting Jason Woodward three-pointer.

SANZAR judicial officer Nigel Hampton QC deemed Horwill's comments to be "a not particularly serious case of misconduct" and took into account that they came 30 seconds after fulltime.

"The consequences that followed was very raw and fresh in the player's mind and led him to vent his frustration in the way he did," Hampton ruled.

"Mr Horwill has an outstanding prior record at all levels and is a recognised leader both nationally and internationally and I accept he is genuinely contrite, with the offer of an apology coming at his own volition.

"I balance against these features of character and past conduct with the fact that Mr Horwill should have known full well the need for respect to be shown to all match officials at all times."

The fine was half that which former Brumbies captain Matt Giteau was slugged after slamming the refereeing of Walsh in 2011, while Eddie Jones copped a $10,000 punishment for a long tirade against Matt Goddard in 2007.