The Automobile Association (AA) expects an increase of 32 cents a litre (c/l) for petrol and 30c/l for diesel.
Illuminating paraffin will likely jump by 22 cents, if current trends continue.
The AA based its estimation on unaudited data from the Central Energy Fund.
In June, petrol increased by 82 cents a litre while diesel climbed by 85c/l.
This pushed prices to record levels in June.
If the latest hikes do materialise, drivers will pay a new record price of over R16 for a single litre of fuel.
The latest figures by Statistics South Africa revealed retail sales dropped by 1,2 percent in April.
This is over and above the biggest decline in nine years of gross domestic product (GDP) growth.
Meanwhile, the BankServAfrica Economic Transaction Index for May declined by two percent between May and April.
This was the largest decline since September 2013 and was a clear showing of the weakening South African economy.
Business confidence also took a knock in the second quarter of 2018, according to data released this week.
At least 60 percent of respondents said they were dissatisfied with prevailing business conditions.