Dragons head coach Bernard Jackman has criticised referee Ian Davies over his handling of their 15-23 Pro14 defeat by Cardiff Blues last weekend.
Jackman says Davies was "inconsistent" and backed Ross Moriarty, who showed his frustrations on the night.
"When Ross sees decisions that are completely mindboggling over 80 minutes he is bound to get a little upset," said Jackman.
He added: "There were very strange refereeing decisions, very poor."
Jackman highlighted a number of incidents that irked him and his players, including Wales and British and Irish Lions forward Moriarty.
"If you look at the high challenge (by Blues wing Jason Harries) in the air on Dafydd Howells, he (Davies) does not want to look at it," said former Ireland hooker Jackman.
"There is an elbow to the face on Ross Moriarty on the ground and he ignores it.
"Ross is blocked on a kick-chase, which is blatant and he (Davies) does not want to look at it.
"It is very frustrating and I can understand why Ross was frustrated."
Jackman added: "It is not acceptable in a match of that magnitude to have such a poor performance.
"That is nothing against the Blues because they were excellent and deserved their win."
Edinburgh boss Richard Cockerill criticised Davies in September, saying he did not officiate their 17-10 win over Connacht "properly".
The Dragons are in European action this weekend when they travel to play Romanian side Timisoara Saracens on Saturday in their Challenge Cup opener.