At least 21 000 motorists have bought their e-tags just after the commencement date of Gauteng's electronic-tolling system was announced, the transport department said on Sunday.
"In the midst of anti-tolling campaigns, motorists have still gone out in their numbers to prove that they are law abiding citizens," the department said.
It added that it was encouraged by reports of long queues at some e-toll outlets across Gauteng.
The South African National Roads Agency Limited (Sanral) has indicated that at least 735 000 tags had been sold.
"Minister [Dipuo] Peters has equally commended those who have already registered, and are in possession of their tags, for doing the right thing."
Peters announced that e-tolling in Gauteng would begin on December 3.
Bill sent through post
Road users without an e-toll account, or a day pass, have a seven-day grace period to pay from the time he or she passed the gantry.
A bill would be sent through the post if the account was not paid within seven days, the department said.
"We are aware of campaigns discouraging people from registering and we wish to encourage motorists to not to pay attention to such." – Sapa