A truck ploughed into several cars near the Voortrekker Road offramp during rush hour traffic.

JOHANNESBURG - Paramedics are treating several patients on a Gauteng highway after a fatal truck accident on the N12 near Alberton on Tuesday morning.

A truck ploughed into several cars on the Voortrekker Road offramp during rush hour traffic resulting in the death of two people with 18 others injured.

Officials believe the driver of the vehicle may have been speeding.

Motorists have now been advised to avoid the N12 east as traffic is severely congested.

Ekurhuleni emergency services say two vehicles also burst into flames.

The mangled wreckage of cars remains strewn across the highway.

Anxious family members are waiting on the side of the road and those who made it out unscathed are still too traumatised to speak.

An eyewitness described the carnage.

"People were lying around and one guy was already dead. A car hit a petrol tanker. The tanker almost spilled over to the opposite direction as well."

The highway is completely sealed off as Ekurhuleni emergency services are giving medical attention to those in need.

Officials say the highway will remain closed until the emergency services have completed their work.

The #N12 in Alberton remains closed following a major accident involving 46 vehicles. Photo via @metro_brian pic.twitter.com/7wV0yIgLvJ.

Jacaranda Newsteam (@JacaNews) October 14, 2014



Oh my God. :( :( RT @MedixGauteng: Massive accident N12 East before Voortrekker rd in Alberton. pic.twitter.com/x8TuJsEVOT

Boitumelo Thulo (@Boity) October 14, 2014



#JHBtraffic Alberton - AVOID huge delays from the R59 North RT @ewnupdates: N12 East closed after 'horrific' accident http://t.co/bKH4cQSXEj