A semi-trailer that burst into flames on the Gateway Motorway this morning has been towed, police say.

The truck, believed to be carrying recyclable plastics, caught fire on the motorway at Belmont this morning sending smoke billowing over surrounding areas.

Motorists faced lengthy delays, while emergency services extinguished the blaze.

Two northbound lanes and the Old Cleveland Road exit were closed, affecting traffic in both directions.

The charred semi-trailer was towed about 7.50am, a police spokesman said.

Jay Lane from the Australian Traffic Network said congestion had since eased.

‘‘Traffic through there isn’t that bad. It’s flowing quite well,’’ he said.