The National Treasury has called the collusion that took place between 17 banks "unbridled greed", while several banks implicated face heavy fines, Business Day reported.
On Wednesday, the Competition Commission announced that it would prosecute local and international banks for manipulating the foreign exchange market. The collusion allegedly took place from 2007-2015.
According to the newspaper, Treasury said that the behaviour of the banks "has potential to collapse national and global financial systems". Absa, Citigroup and Barclays will not be fined because they co-operated with the investigation, but Investec and Standard Bank "face a cumulative R69.7 billion in fines, representing 10 percent of their turnover for each of the years they have breached the Competition Act", said Business Day.
The Competition Commission reportedly worked closely with the US Department of Justice. The case will go to the competition tribunal, possibly later this year, according to the paper.
Fin24.com reported that regulatory reform of the sector was "well under way".
National Treasury's statement also said that it was cases like this that were behind the touted "twin peaks" legislation now in the pipeline.
While the Reserve Bank is a "prudential banking supervisor", Fin24 reported, the legislation would create a market conduct regulator, as well.
Treasury said market abuses like this showed up the "light touch" regulatory system in place, globally, before the 2008 financial crash.
It said regulators around the world had embarked on more "intensive, intrusive, effective" regulations since then.