His seething critique of the NRL referee bunker, labelling two key decisions “embarrassing” and “incompetent” resulted in a $10,000 fine being issue on Tuesday afternoon.

However, he has held fire on making changes for St George Illawarra’s crucial clash with South Sydney at the SCG.

After the loss to Newcastle, which has put them on the brink of falling out of the top eight, McGregor named an unchanged starting team in the 21-man squad announced on Tuesday.

Matt Dufty remains at fullback, with Josh Dugan in the centres.

Their top four hopes all but over, the Dragons are now only ahead of Penrith on points differential with five games remaining.

NRL head of football Brian Canavan said McGregor’s comments “cross the line” in handing down the fine.

“In simple terms, the rule is that coaches, players and officials should not discuss referees and their performances in the public domain,” Canavan said. “We have been pragmatic in dealing with instances where comments have been made but the competence and integrity of referees has not been questioned.

“But it is our view that these particular comments crossed the line.

“All coaches should be aware that they risk sanctions if they discuss the performance of referees.”

Tim Lafai and Nene McDonald were denied tries on review, as they fell 21-14 to the lowly Knights. St George Illawarra have lost six of their past eight NRL games.

In a statement, the Dragons offered no further comment about the fine, saying the club has five days to respond to the breach notice.

The Rabbitohs clash at the SCG is part of the NRL’s heritage round.