Australia are unhappy over what they believe were a number of personal attacks by supporters on players that crossed the boundaries of decency in a series that has seen heated incidents on the pitch.
"I think it’s been disgraceful, you are talking about abuse of players and their families, it’s not on anywhere in the world," Lehmann told reporters after the second day's play.
"You can have your banter, but they have gone too far here. We have written to Cricket South Africa, we will wait to see their response."
One spectator was ejected from the members’ area at Newlands when he initiated a heated verbal exchange with Australia's opening batsman David Warner, who was climbing the stairs to the dressing room after being dismissed before lunch.
"They (the crowd) have got to be better than that when they come to international events, it’s just disgraceful,” Lehmann added. “Not on this level, we cannot accept it anywhere in the world, talking about players and their families.
"There have been various incidents throughout the series, but it has been particularly bad in this test."
Five players in the series have already been sanctioned by the International Cricket Council (ICC) for various contraventions of the organisation’s code of conduct, and it appears South African supporters have picked up on these cues.
There was a heated exchange at tea on the fourth day of the first test in Durban, when Warner accused South Africa wicketkeeper Quinton de Kock of making comments about his wife, Candice.
He served a volley of abuse in the direction of De Kock, which was caught on CCTV cameras in the players’ tunnel.
The build-up to the third test was also filled with controversy as the number one bowler in the world, Kagiso Rabada, a home favourite, was initially suspended and then handed a reprieve after brushing against the shoulder of Australia captain Steve Smith in the second test.
Australia are 245 for nine in their first innings, 66 runs behind South Africa's total of 311. The series is level at 1-1.
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First Published: March 23, 2018, 11:01 PM IST