Johannesburg - Copper worth R12.4m was stolen in December last year, the SA Chamber of Commerce and Industry (Sacci) said on Friday.
That was up from the November figure of R12.2m, recorded by Sacci's copper theft barometer.
The December increase was the first monthly rise since July 2012.
The copper theft volume indicator recorded a level of 179 metric tons in December, from 180 tons in November, and 200 tons in October 2012.
Sacci CEO Neren Rau said the international spot price of copper increased to a monthly average of $8 053 (R71 671) in January 2013, from $7 971 (R70 941) in December and $7 700 (R68 530) in November.
"The volatility of the copper price speaks to the general uncertainty over the course of the global economy over the next six months," Rau said.
"Improved global investor confidence following further stabilisation of government debt in developed economies should force the price of copper upward over the short to medium term."
The past year had shown a favourable downward trend for copper theft, despite the slight increase in December.
Rau said vigilance against every level of the copper theft criminal network could lower the crime.
On Thursday, Passenger Rail Agency of SA (Prasa) blamed copper theft for a train accident in Saulsville in Pretoria.
At least 200 people were injured when a train rammed into the back of another which was stationary.
Prasa said at least 50m of copper cable had been stolen from different parts of the railway track.
No deaths were reported.