Liverpool manager Kenny Dalglish has expressed concern that "the ones who shout the loudest get more beneficial decisions" from referees as he prepares to lock horns with Sir Alex Ferguson in the North-West derby.
Ferguson was charged with improper conduct by the FA following Manchester United's 2-1 defeat at Chelsea in midweek after he spoke out against referee Martin Atkinson, who awarded Chelsea a penalty and neglected to send off David Luiz despite two off-the-ball challenges.
Dalglish, who did not mention Ferguson by name, stressed that his hope that such comments would not influence officials' decisions in United's favour.
"Sometimes I worry that the ones who shout the loudest get more beneficial decisions - and that is totally unfair," he said.
"This week the theme has been about referees and I've got to say that when I came back in as manager I was made fully aware of the respect campaign with regard to officials. I think we have adhered to the campaign in every respect.
"We have never come out and criticised match officials in any of our games. They have made mistakes in all of our games, but we've also made mistakes.
"It is impossible for officials not to make mistakes, but there is a respect campaign in football and I want to know whether we are going to be the only ones that adhere to it.
"I hope that we aren't going to suffer as a club because we show respect to officials. We will continue to respect the campaign - but only as long as we don't suffer in any way, shape or form because of it.
"At this particular moment, I don't think anyone can argue that we haven't suffered. We gave a good account of ourselves in the FA Cup tie at Old Trafford when we lost to a poor penalty decision made in the first minute and then had Steven Gerrard sent off.
"We will try our best to retain our dignity and show respect to referees, but we would also like to think they give us the respect we deserve by at least trying to go along with the guidelines of the campaign. Everybody thinks they are hard done-by by referees - and you are at some stage - but sometimes you get some benefits as well."
Former Reds boss Rafael Benitez echoed Dalglish's comments. "The people who are doing the right things have to have some benefit and, to the people that are not doing this, someone has to say, 'Enough is enough'," he said in the Mail on Sunday.
FIFA president Sepp Blatter, who said on Saturday that the FA could have thrown the book at Wayne Rooney for his actions against Wigan, was also critical of the United boss.
Asked about Ferguson's attitude towards referees, Blatter said: "Respect starts with self-discipline. This is what we are asking for everywhere, from youth teams upwards.
"The higher your position, the higher your responsibility. Those who have more power should be more responsible towards others."