"Ten dead, thirty injured have been admitted to the hospital," said Abdul Qayoum Pukhla, provincial health director of Kandahar.
The incident happened in rural Panjwayi district, southwest of Kandahar city, and was confirmed by Panjwayi's district Chief Fazluddin Agha.
"Yes, there was an explosion killing and injuring road workers but I don't have the exact number of casualties," said Agha. The injured were evacuated to hospital in Kandahar city.
One survivor who did not want to be named said there were a total of 40 people on board the truck.
Kandahar, the birthplace of the Taliban, is one of the most violent provinces in Afghanistan and is frequently hit by major attacks.
Earlier this month, the city -- the de facto capital of southern Afghanistan -- came under siege for two days as the Taliban unsuccessfully tried to seize control of a string of government offices.
International forces say the province is now more secure following major battles to secure ground in 2010.
There are around 130,000 foreign forces in Afghanistan, of which 90,000 are from the United States.(AFP)