Outa might have to drop its court challenge to e-tolling on Gauteng's highways if it does not raise an extra R1-million in three weeks, chairman Wayne Duvenage said on Wednesday.

"There is a very real chance if we do not get this money this matter will not be heard," Duvenage said at a press conference to appeal for the money.

The Opposition to Urban Tolling Alliance (Outa) had until June 21 to raise the money.

It had so far raised R8.4-million through donations and still owed about R3-million in legal fees. Without the R1-million payment to lawyers, the case might not go ahead.

Outa had received donations from over 200 businesses, ranging from R100 000 or the amount they would have paid in toll fees for their fleets; and about 7 780 individuals, starting from around R20, towards their legal fees.

During the news conference, two more organisations announced they would throw their weight behind Outa.

The Gauteng chapter of the Black Management Forum's management committee member, Stan Itshegetseng, said the BMF wanted to dispel the notion that it was only "fair skinned" people who had an interest in the case.

"It is going to increase the general cost of living," he said.

The QuadPara Association also supported the court action, representative Joseph Machweu said from his wheelchair, adding that e-tolling would make travelling more costly for members.

Duvenage said lawyers had donated much of their services, but still had some costs they could not cover themselves in what was a technical case.

The announcement that the cap for toll fees would drop from R550 to R450 did not make a difference, he said.

Outa believed government should concentrate on covering the cost of the road, not technologies, such as licence plate tracking, and should rather cover the road maintenance costs through the fuel levy.

Father Mike Deeb, co-ordinator of the justice and peace department of the SA Catholic Bishops' Conference (SACBC), called on government and members of Parliament to not go ahead with the project.

The SACBC recently joined a wide range of NGOs and civil society groups opposed to e-tolling.

He said the church knew it was difficult to oppose it and for MPs not to vote in favour of it, but he urged them not to co-operate.

Outa has led a court challenge to the introduction of e-tolling, funding it through donations.

In April, the SA National Roads Agency Limited (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.