Swans boss Roberto Martinez has also voiced his disappointment regarding the incident, however Wellens has adamantly denied spitting on Britton.
"I am disappointed that Leon Britton has come out in the newspapers and on the web with the accusation that I spat in his face, which he quite clearly later says was not a face to face spit," he told the club's official website.
"He also called me a coward, which I found distasteful; as in 10 years and over 400 games I have never been called that.
"I did not spit in his face, but as usual I was clearing my throat and did not aim anything his way. No one, including their manager, can say they saw me spit in his face."