This is the heartwarming moment a kind truck driver helped pick up and put on a fallen motorcyclist's prosthetic leg in Malaysia.

Dashcam footage shows the driver wearing red shirt stepping out of his lorry and walking towards the other lane in a busy road in Penang state on September 21.

He then approached the rider and handed him the artificial plastic limb that he picked up near his truck.

After fitting the prosthetic leg back, the driver casually returned to his lorry and went on his way.

Touched onlooker Nicky Tsuragi said: ‘The truck driver was very kind. Helping other people seemed very normal to him, like breathing.

‘He did what he had to do and left without waiting for anything in return.'

Nicky added the other drivers stopped until the rider was able to wear the artificial limbs again.

He said: ‘It was a very rare moment for me to see such kindness on a busy road. Most of the time, there's just rage in slow traffic. That time was different.'

The rider left shortly after the lorry driver and traffic returned to normal.