Copper theft in the country declined from R23 million in May to R17.9m in June, Sacci said on Monday.
The SA Chamber of Commerce and Industry said its Copper Theft Barometer showed a third substantial decline since the peak of R34.7m in March 2012.
Furthermore, Sacci's new Copper Theft Volume Indicator recorded the theft of 288 tons of copper in June, down from 356 tons in May, a 19 percent drop on a monthly basis.
The volume indicator provides an indication of how much copper is stolen, as opposed to its rand value.
"The declines in both the barometer and volume indicator confirm that copper theft levels have dropped substantially over the course of the second quarter of 2012," said Sacci.
In July, the international spot price of copper increased to an average of US7599 (about R62,209) per metric ton from the US7427 (about R60,801) average in June.
This was the first increase of the monthly average copper price since March 2012.
Sacci said the long-term relationship between the international price of copper and South African copper export volume remained because of the impact that higher prices had on the value of the exported goods.
"The outlook for the fight against copper theft looks positive given the latest data from the barometer and volume indicator."
The chamber welcomed the proper training of police officers in the finer aspects of detecting and policing copper theft in terms of the Second-hand Goods Act.