The Rugby Football Union has warned Harlequins' Conor O'Shea and Leicester's Richard Cockerill about their future conduct after the duo's recent criticism of match officials.
O'Shea criticised referee Llyr Apgeraint-Roberts' decision making after his team's 31-26 victory over London Welsh last weekend.
And Cockerill slammed Andrew Small's performance after Leicester's 17-12 win over Gloucester last month - a match in which the referee handed out four yellow cards.
The RFU has now written to the pair warning them that they could be charged with bringing the game into disrepute under RFU Rule 5.12 and added that the coaches should use the "existing agreed feedback process" regarding the performances of match officials.
The Rugby Coaches Association's chairman Sir Ian McGeechan has also voiced his opinion about the state of officiating at club level in England.
"Consistency in refereeing is what all involved in the game need more than anything," he said.
"Coaches and players recognise that referees have a difficult job.
"The chaotic nature of the game, the pace that it is played at today and the technical aspects of the set pieces in particular, make for difficult decision-making.
"We don't expect the match officials to make the right decisions every time, however, we would like consistency from week to week."