Spokesperson Tami Didiza said that the rise was in line with other developing markets and lower than in developed countries, and that the company expected to introduce further increases.
"We believe that prices will firm further in the international markets, due to demand and cost pressures," he said in reply to emailed questions.
ArcelorMittal South Africa based its prices on global trends, using a price basket from a number of countries.
Didiza said that the latest increase equated to an average rise of R450/t, which was between 4% and 6%, depending on the product.
"The price increase of both flat and long steel products was calculated according to international price trends, and reflects price levels below current orders booked for forward delivery," Didiza said.
He illustrated that the price for hot-rolled coil in the North American market was currently $1 200/t, $1 140/t in the European market and $1 030/t in the Black Sea market.
"The effect of this price on the comparable product in South Africa will be $1 050/t," he stated.