The Opposition to Urban Tolling Alliance (Outa) welcomed a ruling by the High Court in Pretoria on Friday granting it leave to appeal against a previous judgment made by the court.

"[It is]... the alliance's sincere belief that their case to halt e-tolls has strong grounds, which we trust will eventually obtain the ruling that Sanral's current e-toll plans are illegal," Outa executive Musa Strachan said in a statement.

"Outa wishes to thank the thousands of citizens and hundreds of businesses that have contributed to funding this campaign."

It said it was "mindful" that the South African National Roads Agency Limited (Sanral) could continue with the project and not wait until the appeal was heard in the Supreme Court of Appeal (SCA) in Bloemfontein.

"They will have to do so knowing full well that the SCA could rule the scheme as illegal, in which case it may have to be halted," Strachan said.

On Friday, Judge Louis Vorster granted Outa leave to appeal his previous judgment on e-tolling to the Supreme Court of Appeal.

"The order I make after some consideration is the following: leave is granted to the applicants to appeal to the Supreme Court of Appeal against my previous judgment handed down on 13 December last year."

He deferred the matter of costs to the SCA.

Vorster did not detail his reasons for the judgment, but said he would provide written reasons when requested.

The Democratic Alliance in Gauteng congratulated Outa.

"It is very encouraging that the Supreme Court of Appeal will now hear this matter," DA MPL Jack Bloom said in a statement.

"It is a vitally important case because it will determine how seriously public views are taken into account on e-tolls and any other government decision, with far-reaching impact."

Mike Maritz, for Outa, argued on Friday that Vorster had "erred fundamentally" in his interpretation of section 27 (4) of the Sanral Act.

He said Vorster had not engaged with the argument against a lack of "procedural fairness" in the way Sanral had informed the public about e-tolling.

Vorster ruled in December that e-tolling could proceed because the Gauteng Freeway Improvement Project had been lawfully instituted. He dismissed Outa's application with costs.

In his judgment, Vorster had said only the physical aspects of the project were up for public debate, and not the costs.

Maritz said it would follow from the judgment that Sanral could have paved the road in gold and charged R50 000 a person through e-tolling, without having to tell them about it.

On Friday, David Unterhalter, for Sanral, and Jeremy Gauntlett, for the Treasury, argued in favour of Vorster's judgment.

Unterhalter said there was no reason to "burden another court" with the e-tolling issue.

He said the "heart of the matter" for Outa was companies with commercial interests.

Gauntlett agreed with Unterhalter, and said Outa was trying to argue it was representing the public when it was not.

"We submit that there is no... [reason] that another court will come to a different conclusion on a cost basis," Gauntlett said.