The player is ruled out for the Springboks' autumn internationals.
Springbok front-rower Wessels has been suspended of nine matches for touching opponent Josh Murphy's private parts during the Blue Bulls' United Rugby Championship win over Connacht.
The incident occurred in the early stages of the close contest against Connacht on Friday, with Connacht forward Murphy receiving a 20-minute red card after reacting angrily by striking Wessels on the head.
After Murphy complained to referee Mike Adamson, the situation was examined by the television match official, who concluded no conclusive video evidence.
The Bulls player stayed on the pitch until he was replaced in the later stages of the match.
Although the URC confirmed that the Irish player's 20-minute red card was overturned by a governing body, Wessels was found to have violated the code of conduct, which states:
"Any athlete must not engage in actions that is contrary to the spirit of good sportsmanship. Such behavior covers grabbing, pulling or compressing the genitals."
Disciplinary officials were satisfied that the contact met the level for dismissal and justified a 12-week suspension, the minimum suspension under World Rugby rules for such an infringement.
Nonetheless, Wessels' suspension was shortened by three weeks because of his good conduct during the proceedings and his clean disciplinary history.
Wessels and the Bulls are entitled to appeal, but as it stands, the suspension will prevent the 24-year-old out of the Springboks' fall internationals against the Brave Blossoms, France, Italy and the Irish team.
Wessels will also miss the his club's league matches against Glasgow, the Lions and the Sharks, as well as European cup games with Bordeaux and Northampton.
Wessels has earned 10 caps for South Africa and was part of their tri-nations champion team over the summer.
The Connacht player, in contrast, is eligible to face Munster in this weekend's domestic clash after being cleared.
Lena is a tech journalist with over a decade of experience covering consumer electronics and emerging technologies.