Chelsea have lodged a formal complaint with the Football Association after alleging Clattenburg spoke out of turn to John Obi Mikel during Sunday's stormy Barclays Premier League clash against Manchester United at Stamford Bridge.
The west London club have submitted a dossier of evidence which contains accounts given by players, who claim the 37-year-old official used a term which has been interpreted as racist.
Police are also investigating the matter.
Clattenburg denies the allegation and it is understood that assistant referees Michael McDonough and Simon Long, and fourth official Michael Jones, also believe he is innocent.
It is understood the trio feel they did not hear anything untoward from the referee during the match on their linked headsets and are expected to say as much in any testimony.
It is also understood that the professional refereeing community as a whole has been deeply upset by the claim against Clattenburg, who himself is determined to clear his name.
Other well-respected current and former referees will offer positive character references for Clattenburg's defence if it is decided the County Durham official has a case to answer to the FA or police.
If the procedure for previous disciplinary cases is followed, Clattenburg is likely to be the last person the FA interviews as part of its enquiries.
It is expected the governing body will firstly look at Chelsea's dossier and then speak to McDonough, Long and Jones before interviewing the man who was in charge of the game.
The matter has dominated sporting headlines since the weekend and notable people in the game have offered their opinions.
Arsenal manager Arsene Wenger has said he would have dealt with the situation differently if it had arisen in one of his team's games.
The Frenchman said at a press conference: "My opinion is just, I prefer when I didn't behave well, that I have an explanation with the referee at the end of the game, or on another day, than going public with little proof you know.
"I'm not a great believer in making these stories public."
He added: "I am a deep supporter of doing that internally.
"If (football) becomes a sport to make the lawyers rich, I am not a fan of it.
"One of the great things in sports as well is tolerance, forgiveness and explanation internally and I think it should stay like that.
"It can happen that a referee doesn't behave well, I do not say they are angels, but it is always better to sort it out in the room."
West Ham manager Sam Allardyce expressed his dismay that police have become involved in another high-profile footballing matter.
Allardyce said: "It's very difficult to comment because you don't know the extent of what is supposed to have been said, that is the critical thing for me.
"For me to comment - I just think a situation like that is very difficult for everybody to sort out, and then the police are involved as well and it really worries me about where we are going in the game.
"I think if every incident is going to end up in the police's hands then it is going to be sad for the game of football in general.
"Over the last however many years as a manager I've never heard one referee give a bad comment to a player so I found it a very strange thing that has been reported but only the authorities can decide if it has or hasn't happened."
Earlier this week Neil Warnock launched an attack on Chelsea for their handling of the affair.
The Leeds boss, whose side will now face the Blues in the quarter-finals of the Capital One Cup, stands by the comments, according to his assistant Mick Jones.
Jones said: "People think (Warnock) says things off the hip but he doesn't, he thinks about things a lot and he's passionate about the Clattenburg thing.
"Believe it or not, he's pro-referees. There is no bigger supporter of referees than Neil Warnock. He won't regret it, he doesn't say things off the cuff, he is a thoughtful man."