Three children have died and more than 50 others have been hospitalised after eating food accidently mixed with toxic insecticide in a school in Peru.

The poisoning took place on Tuesday when the school lunch of rice and canned anchovies was placed in a container that held insecticide residue.

Police said 56 people, including teachers and parents, sought medical treatment in the Cajabamba province in the northern department of Cajamarca, 750km north of Lima.

The three dead were between seven and ten years old, said Aida Garcia Naranjo, Minister for Women and Social Development.

Regional health officials said they fear the death toll will rise.

The food had been provided by the government's national food assistance programme.

The minister said further guidance was needed to properly prepare the food.