Parents in Spain are being urged to "go on strike" against their children being set weekend homework.

The unusual move is being launched for November because of "the absolute certainty that homework is detrimental" to children, according to the head of the group behind it.

The strike has been called by the Spanish Alliance of Parents' Associations (CEAPA), a network covering around 12,000 state schools, and targets weekend homework for primary and high school students.

Jose Luis Pazos, president of the CEAPA, told AFP that weekend homework damages children's extra-curricular development.

A 2012 report said Spanish children got the fifth most homework in the world, with 6.5 hours a week compared to an average of 4.9. The table of 38 countries was headed by Russia, Italy, Ireland and Poland.

However, the same Programme for International Student Assessment tends to give Spanish students low scores in maths, reading and science, despite the higher workload, while in Finland and South Korea - two of the countries with best student performances - the average time spent on homework every week was less than three hours.