Akinfenwa highlighted the incidents in the Chairboys' 2-1 Sky Bet League Two win at the Cambs Glass Stadium on Saturday on Twitter.
He wrote: "Good 3pts 2day, great support again. It's a shame that a small group of Cambridge fans focus on colour rather than the game #KickOutRacism."
Cambridge responded on Twitter asking for further information and have now opened an investigation after receiving the requested details from Wycombe.
The incident was also reported to the match referee, Trevor Kettle, Wycombe said.
Cambridge chief executive Jez George told Cambridge News: "We're in dialogue with Wycombe and we're investigating the situation because these are serious allegations."
Cambridge Fans United chairman Robert Osbourn added: "I am aware that the club is investigating the claims and is seeking to identify those involved so that appropriate action can be taken.
"CFU supports the club's investigation wholeheartedly and would urge anyone who saw and heard what happened to contact the club."