The Opposition to Urban Tolling Alliance (Outa) on Wednesday warned Gauteng e-toll road users to think before being "seduced" by the South African National Roads Agency Limited's (Sanral) offer to register for e-tags.

"Sanral is desperate to get the over 1.3-million non-compliant freeways users to play on their turf by signing their terms and conditions," spokesperson John Clarke said in a statement.

Sanral announced on Wednesday that the grace period for e-toll road users to settle their accounts and benefit from the discount had been extended.

Users would be discounted for the period of December 3, 2013 to February 28, without the alternate user tariff being applied. The alternate rate is three times the standard toll tariff and is for unregistered users.

Outa described the move as a strategy to persuade road users to register so the agency could solve its financial problems.

"Outa predicted that Sanral would re-commence its hook, crook, and spook tactics as soon as the elections were over," the alliance's chairperson Wayne Duvenage said.

He said the alliance believed the discount offer would be followed by a summons case to scare the public into compliance.

Outa unsuccessfully launched a court challenge to stop e-tolls in Gauteng.