A truck overturned in India on Saturday killing 19 labourers who were crushed under cement sacks that fell from the vehicle as it toppled, police said.

Six others were injured in the accident which happened on a busy highway in western Gujarat state, the latest deadly crash on India's notoriously accident-prone roads.

"19 persons including 12 women, three teenagers and four men were killed when the truck coming from Pipavav Port overturned on (the) Ahmedabad-Dholera highway," police superintendent R. V. Asari told AFP.

"All the deceased were labourers going to work in fields in Anand district. All were buried under the cement sacks after the truck overturned."

Asari said it appeared the driver dozed off at the wheel which caused the truck to skip off the road and flip over.

"We are currently engaged in rescue operations. How the accident occurred needs to be investigated. Primarily it appears that the driver dozed off," he added.

In another accident, 11 people were killed Friday in Uttarakhand state when a speeding truck rammed into a group of pilgrims walking towards a temple, the Press Trust of India reported.

India has some of the world's deadliest roads, claiming the lives of more than 150,000 people each year.

Last month, some 13 children were killed after a train smashed into a school bus in Uttar Pradesh state.

And 21 revellers were killed en route to a wedding when their truck flew off a bridge in Madhya Pradesh state.

Most accidents are blamed on poor roads, badly-maintained vehicles and reckless driving.

Commercial drivers are largely unregulated, meaning many work long hours through the night, raising the danger of them falling asleep at the wheel, campaigners say.