The incident happened midway through the second half as Diouf appeared to be felled in the penalty area by the veteran Dutch player, and video evidence has since proved conclusive forcing the Wanderers to take the hard line of action against the player on loan from Liverpool.
Bolton chairman Phil Gartside and manager Sam Allardyce have released a joint statement to the public about the incident and the action which has been taken.
"The club does not tolerate such behaviour from its players and we had no alternative but to evoke the maximum fine against El Hadji Diouf, Bolton Wanderers takes great pride in its very proactive family image and the incident has left a sour taste. We do not condone the actions taken by the player and for that he has been severely punished."
The Senegal attacker issued an apology to all the parties involved in the incident but could still face further punishment depending on what course of action is taken by the Football Association. It is the fourth time in two years that Diouf has been involved in such behavior.
"I deeply regret my actions and wish to publicly apologise to Arjan De Zeeuw and Portsmouth football club, I have let down my manager, Sam Allardyce, and team-mates. I am a role model to many thousands of fans throughout the world and my behaviour showed a lack of moral responsibility to the public who support me. I am deeply sorry and embarrassed about the incident."
The Trotters have also promised to review the player's situation at the club as Gartside confirmed that he will be holding a meeting with the Liverpool chief executive Rick Parry.
He has accepted that he is totally out of order, That wasn't discussed; we have taken the maximum action we can take. I can't take my personal views into this and we have to use the rules stated by the association.
"The whole club is ashamed of the action and we can only take the action we have. We have got to review it, I have spoken to Rick Parry at Liverpool and he is fully supportive of our action and he will review it also,"