There are 538,000 child labourers in the country - and more than half of them are girls, the survey has revealed.

Children across Africa carry a heavy load

Aged under 15 years old, most of these live and work in the rural areas, where they follow the tradition of toil in the fields.

But tens of thousands are sold by their parents as domestic servants in the cities.

The parents receive around $10 a week, while the children are tied to their job in what the BBC's correspondent in Morocco, Nick Pelham, says amounts to near slavery.

The government says it is trying to stamp out child labour. The minister in charge of child protection, Said Saadi, told the BBC that the government is concentrating its efforts on attracting children out of the job market and back into school.

Industry trying to cut costs

It is a major struggle because educational standards are already low.

About 60% of Moroccans cannot read or write. At the same time, industries are trying to cut costs by replacing adults with child workers.

Unemployed parents feel forced to send their children out to work, and the cycle continues.

Boys in Senegal learn their trade very early

Morocco is hardly alone in facing the problem. It is estimated that in Africa as a whole, two in five children under 15 are working. And around the world the total is likely to be some 250m.

The International Labour Organisation has just approved the final draft of a new convention designed to abolish the most damaging kinds of child labour such as prostitution, slavery and trafficking.

The ILO's new director, Juan Somavia, said: "Let us declare the worst forms of child labour morally abhorrent. No parent in the world would like to see his or her child live through them."