Tunis - Seven women day labourers being transported to work on a Tunisian farm in the back of a pickup were among 12 people killed when it collided with a minivan on Saturday, the emergency services said.

Unofficial casualty figures put the toll at 15 killed.

The deaths triggered an outcry on social media, with users accusing farm owners of treating their low-paid, mainly female workforce "like cattle".

Others called the accident a "state crime" and "intentional form of neglect" by local authorities as security patrols should not have allowed the transportation of so many women in unsafe conditions.

Both drivers were also killed in the dawn crash with the minivan carrying poultry in the poor central region of Sidi Bouzid, emergency services spokesman Moez Triaa said.

Health ministry spokesman Chokri Nafti said 21 people required hospital treatment for injuries sustained in the crash.

Videos and pictures circulating on Facebook showed the victims' bodies laying on the ground as emergency vehicles rushed to the area.They also showed dramatic scenes of families grieving near-by.