Collymore claimed he was "hurt and angry" after the remarks from Harkness and that he had deliberately informed black players at Anfield about what was allegedly said.
However, Harkness said: "I vehemently deny the accusation that I made racist comments to Stan Collymore during or after the game at Aston Villa on Saturday.
"The particular background to this game may have meant that there was more going on on the pitch than is usual, but that does not extend to racial abuse of any kind."
Before Harkness spoke out, it was revealed that Brendon Batson has been called in as an arbitrator by Liverpool as they consider their response to the claims from Collymore. The Professional Footballers' Association assistant secretary travelled to Anfield yesterday to take part in the inquiry launched by Liverpool in the wake of the allegations from their former striker.
Batson said he was "bewildered, upset and definitely determined" to destroy racism in football. He added: "Was it just two players arguing in the heat of the moment? I hope it was and not anything else. If we find one person was racist then this organisation will come down hard on them."
With the Football Association considering an independent inquiry of its own - regardless of whether Collymore makes an official complaint against Harkness - Liverpool's top officials were locked in meetings yesterday. The club promised to make a statement after top-level discussions at Anfield that included the player, the manager, Roy Evans, and chief executive, Peter Robinson.
Evans said: "I don't intend to say anything about Stan's comments. It is in the hands of the club's top people now."
Collymore, who scored both goals in the 2-1 victory for Villa over his old club, has not decided whether to make his complaints official - or let the incident blow over.
Collymore's agent, Paul Stretford, said: "I have been kept informed of what has been going on, but neither I or Stan will make any further comment at the moment."
The Villa manager, John Gregory, promised that the club would give Collymore their full backing should he decide to take the matter any further.
"We will back him 100 per cent," Gregory said. "The club will be in total support of Stan. I'm disgusted, to be honest, that something like this has happened on a football pitch, because we have a number of coloured players and they are superb people.
"But, as a club, at present we're not going to take up anything further with the Football Association."
Gregory revealed that Collymore was furious after the game. He said: "Not only was he taking stick physically, he was also taking a lot of verbal abuse. It did affect him and it took him a long time to calm down after the match."Reuse content