Cape Town and Gauteng are experiencing shortages of certain fuel types, the Fuel Retailers' Association (FRA) says.
"Some service stations [are] reporting being dry for six to seven days on one or two products," FRA chief executive officer Reggie Sibiya said in a statement.
"Diesel and ULP95 are topping the product list of shortages."
Last month, Durban suffered a shortage of low sulphur diesel.
On Thursday, Sibiya said depots in Alrode, Langlaagte, Watloo and Killarney in Gauteng had delivery problems. BP and Caltex were the two companies who seemed to be the worst affected.
Sibiya claimed oil companies were not providing fuel retailers with a proper explanation about the shortages.
The FRA is an independent body which promotes the interests of fuel retailers.