MORE: 3rd ODI Preview and Live Scores - Australia v South Africa
The South African quick and Clarke first clashed at the culmination of Australia's Test series win in South Africa in March.
Their war of words was reignited during the triangular one-day series with hosts Zimbabwe, which the Proteas won in September, when Steyn first commented on the incident.
And the top-ranked Test bowler said he did not want to start a public bust-up with the Australian skipper, and was regretful of responding to questions about the heated finish to the Test series.
"The issue got blown out completely, it was like two schoolgirls the way the media got hold of it," Steyn said ahead of Wednesday's one-dayer.
"I felt like Clarkey had his opportunity to say something at the end of the Cape Town Test and obviously I wasn't in the press conference there and the next opportunity I got was a couple of months later in Zimbabwe so I said what I felt.
"It wouldn't have been fair if I'd said something straight after, I would have been called a sore loser after losing the series or the match so I just kept my mouth closed until it was my turn to say something. I didn't want it to start a massive thing.
"It did, doesn't matter."
South Africa produced a gritty three-wicket win over the Australians in Perth on Sunday to level the five-match series at 1-1.
It looked like it would be a canter for the Proteas in the second ODI as Morne Morkel's five wickets helped destroy the Australians, dismissing them for 154.
Given such a paltry target to defend, the Australian attack battled gamely - Josh Hazlewood's 5-31 gave the South Africans some anxious moments, but ultimately AB de Villiers' 48 helped the tourists to a nervy victory.
The Australians have rung the changes for the clash in the capital, with strike bowler Mitchell Johnson rested for the remainder of the ODI series to focus on their upcoming Test rubber with India.
Johnson's omission hands chances to the likes of Pat Cummins, and left-armer Mitchell Starc, who were drafted into the squad.