Du Plessis was caught tampering with the ball on the third day of the second Test in Dubai. But he escaped with only a fine of 50 percent of his match fee after he pleaded guilty to the charges, by Australian match referee David Boon.
A senior official of the board told PTI that a letter will be dispatched to the International Cricket Council tomorrow asking for a review of the match referee's decision.
Meanwhile, Pakistan cricket fraternity expressed their unhappiness over the episode and accused the ICC of unfair treatment.
The chairman of the PCB interim management committee Najam Sethi tweeted about his disappointment and confirmed the board would take up the issue with the ICC.
"We want to know why this anomaly in imposition of penalties, why are they different set of rules for Plessis and Shahid Afridi?," Sethi asked.
Afridi, too, expressed sadness over discrimination by the international body.
"I don't know how to say this but there appears to be a clear discrimination when it comes to imposing penalties for rule violations for us and others," Afridi told reporters.
