Motorists using Gauteng freeways without e-tags will face steep charges once the new toll-fee structure comes into effect.

Cabinet spokesman Jimmy Manyi was adamant yesterday that the tolling of Gauteng's freeways was now irreversible and that the announced fees were final.

"This is not just a bad dream, it's reality, it's going to happen. No one should have any illusion whatsoever that this thing is going to go away. It's a fact of life and it's going to happen," he said.

"Law-abiding citizens, buy your e-tags, e-toll is coming. Don't harbour any thought that this might go back."

He said the government was prepared to deal with those advocating civil disobedience over the tolls.

"If you are not going to obey the law, the law will take its course. Period. I want this to be abundantly clear."

The planned tolling of Gauteng freeways was introduced to help the roads agency repay over R59-billion it had raised to upgrade roads nationally. Gauteng freeways cost R20-billion to upgrade.

But labour federation Cosatu is advocating a civil disobedience campaign and has encouraged motorists not to pay when the bills are posted to them.

Cosatu secretary-general Zwelinzima Vavi said on Wednesday after the announcement of the budget by Finance Minister Pravin Gordhan that workers would protest against the tolling.

In terms of the pricing structure, tolls for vehicles using the freeways regularly will be capped at R550 a month. Heavy-duty vehicles qualify for a 20% discount if they drive during off-peak hour periods.