The Opposition to Urban Tolling Alliance (Outa) has raised R2.35-million which will go towards its court challenge to e-tolling on Gauteng's highways, it said on Tuesday.

"Just five days later we are able to announce that over R1.35-million was raised from the public, plus a further R1-million contribution on Friday from the DA," Outa chairman Wayne Duvenage said in a statement.

"We certainly did not expect this significant answer to our call and want to thank each and every person and organisation that took the time to contribute."

Last week, Outa said it might have to drop its court challenge if it did not raise an extra R1-million in three weeks. It had until June 21 to raise the money.

It had taken Outa a year to raise R8.4-million, of which R6.7-million came from 220 businesses, so to raise R2.3-million in less than a week was a sign of the support for the anti-tolling campaign, said Duvenage.

Outa was now preparing its heads of argument for the forthcoming court battle.

However, Outa was concerned about the SA National Roads Agency Limited's (Sanral) indication that e-tolling would be launched in July.

"We are in for an interesting period if Sanral tries to introduce their toll plans, just two months prior to the court challenge which could very well rule that e-tolling must be halted," said Duvenage

"Sanral could find themselves in a quandary of having to refund customers, or press on with another appeal, in an ever-growing environment of rejection by society."

In April, Sanral said it would begin e-tolling on Gauteng roads within two months.

Last April, the High Court in Pretoria granted Outa an interdict approving a full judicial review before electronic tolling could be implemented.

The interdict prevented Sanral from levying or collecting e-tolls pending the outcome of the review. Sanral and the National Treasury appealed the court order.

In September, the Constitutional Court set aside the interim order. In December, the High Court in Pretoria dismissed Outa's application to scrap e-tolling.

The court granted Outa leave on January 25 to take the matter to the Supreme Court of Appeal in Bloemfontein. The appeal is expected to be heard on September 25 and 26.