Warner breached an article of the Code of Conduct for Players and Player Support Personnel relating to "public criticism of, or inappropriate comment in relation to an incident occurring in an international match or any player..." the International Cricket Council (ICC) said on Thursday.
There was no need for a formal hearing as Warner, who made the allegation in a radio interview, accepted the sanction from match referee Roshan Mahanama, the ICC said in a statement.
"It was disrespectful for David to publicly denigrate an opponent when commenting on a match-related incident, and imply that a South African player was engaging in sharp practice. I'm sure David will be careful when making public comments in future," Mahanama said.
The third and final test starts in Cape Town on Saturday with the series level at 1-1.
(Reporting by Nick Said; editing by Amlan Chakraborty)
