Outa says the details of the electronic toll collection contract should not be kept confidential, despite efforts to keep the information locked away.
"It shouldn't be confidential. It is taxpayers' money that is being used to pay the tolls, so the taxpayer should know what the money is being used for," said Opposition to Urban Tolling Alliance (Outa) chairperson Wayne Duvenage.
However, there was nothing he could do about it after Outa agreed to sign a confidentiality agreement, said Duvenage.
He said this was the only way Outa would have been able to get access to the ETC contract to prepare for its court case.
Duvenage was responding to a report in the Star newspaper on Monday that parts of the high court review of the project in November could be held in camera because of the confidentiality agreement.
This meant the public might never know the full agreements, pricing and subcontracts surrounding e-tolling.
The South African National Roads Agency Limited (Sanral) initially told the public the e-toll tender was R6.2-billion. But it later emerged this figure appeared to be escalating and figures of R9-billion, R15-billion and even R30-billion to operate the system were surmised, the paper reported.
Government-appointed attorneys Werksmans responded by email on September 6 telling the alliance they would supply documentation only if a confidentiality agreement was signed.
The Star quoted the email as saying if the alliance did not agree to the confidentiality, their clients would file opposing papers "which will challenge the issue of urgency" and they would file a "substantive response to your client's affidavit, which will delay the hearing of the application".
The confidentiality agreement declared that the information of the documents could not be given to any third party.
"That some, if not all, of the information requested contains information that is proprietary to our client and that it is imperative that the integrity of this information is maintained within the parameters outlined above," the e-mail read.
"It is and remains our client's view ... that the documentation and information requested… are and remain irrelevant to the issues required to be determined in the review application," the paper quoted.
Last month, the Constitutional Court overturned an interim order which put a hold on the Gauteng e-tolling project.
During the case, the legal team representing Sanral made selective references to the ETC contract, which Outa had not seen.
"Now imagine a court case for them to use the contract even though we had not seen it," said Duvenage.
"We needed to see them ... so we were asked to sign a confidentiality agreement to see it."
The Democratic Alliance said the signing of the confidentiality agreement was suspicious.
"We have to ask why does Sanral appear to be hiding something and who is it seeking to protect?" DA parliamentarian Neil Campbell asked in a statement.
He said full disclosure had to be given to Gauteng residents.
"This case should take place with unrestricted public access despite indications that Sanral wants part of it to be held behind closed doors," said Campbell.
"Anything less than full disclosure will confirm that Sanral and the government have something to hide."
He said Parliament, on request, received 27 of the 33 contracts relating to the e-tolls. The others were not given.
'Thick veil of secrecy'
"Why are the other six contracts not forthcoming?" he asked.
"The latest in the smoke and mirrors saga is the confidentiality requirement which adds to the thick veil of secrecy surrounding e-tolling."
This added to speculation that someone at Sanral or in the government stood to make "a pot of money" from e-tolling, said Campbell.
The Constitutional Court found that the North Gauteng High Court in Pretoria had not considered the separation of powers between the high court and executive.
In April, the high court granted Outa an interdict, ruling that a full review needed to be carried out before electronic tolling could be put into effect.
The interdict prevented Sanral from levying or collecting e-tolls pending the outcome of the review.
Sanral and the national treasury appealed against the court order and said delays prevented the payment of the R21-billion incurred in building gantries.
The review was expected take place in the North Gauteng High Court in Pretoria on November 26. – Additional reporting by Sapa