PORT ELIZABETH: Level two offences are for the conduct of a serious nature. In Rabada's case, the alleged offence is that of making inappropriate or deliberate contact with another player.
Rabada shouted in celebration and approached Smith aggressively after winning a leg before wicket decision against him and the shoulders of the players made contact.
It is the second incident of a bad-tempered series after Australia's vice-captain David Warner was fined 75 percent of his match fee for an altercation in a stairwell with the home side's wicketkeeper Quinton de Kock.
The charge against Rabada was brought by the on-field umpires, Kumar Dharmasena and Chris Gaffaney. The hearing will be conducted by International Cricket Council match referee Jeff Crowe.
A Cricket South Africa spokesperson said Rabada would defend the charge and argue that the contact with Smith was accidental.
If found guilty Rabada could be fined between 50 and 100 percent of his match fee and could be penalised three or four demerit points. Because he already has five demerit points, which led to him being suspended for a Test match against England last year, Rabada could be liable to serve another suspension, which could rule him out of the two remaining Tests in the series.