Consumer prices rose to 7.8 percent in July after reaching 7.4 percent in June, the national statistics agency StatsSA said in a statement.
For South Africans, it has resulted in rising costs for necessities including food, electricity, fuel and medication, the government said.
Prices for breads and cereals were up 13.7 percent in July, from 11.2 percent in June. It means a loaf of white bread now costs 17.84 rand ($1.05) compared to 15.57 rand ($0.91) on year ago, the statistics agency said.
The price of fuel increased by 56.2 percent from last year.
The rising cost of living is taking a toll on the public, where the jobless rate hovers near 34 percent.
On Wednesday, the country's two largest trade unions led a protest in major cities over the worsening economic conditions, which have been particularly crippling for the poorest.
Strikers were demanding government action to rising poverty and the cost of living.