Nepal is teaching self-defence to quake-affected women and children following a string of attacks in temporary camps housing survivors, police said Friday.

More than 8,700 people died in two major quakes that hit Nepal on April 25 and May 12, destroying nearly half a million houses and leaving thousands camping out in the open.

"Cases of abuse and violence have been reported in the camps, and some women complain of feeling insecure living there," said police official, Tara Devi Thapa, who is coordinating the classes.

"These skills will help them feel confident against attackers and will be useful for their protection," Thapa told AFP.

On Friday morning, dozens of women took a break from chores and brought their children to an open ground in a camp in Kathmandu, as an all-female police team taught them basic judo and karate moves.

"Don't think you are weak just because you are a woman," said constable Pramila Khadka.

"Listen to me attentively, and you won't have trouble tackling even someone stronger than you," Khadka, a judo player, told the women.

Taking turns at playing attackers, the participants partnered with each other and practised kicks, punches and locking moves designed to disarm opponents, as police shooed away curious male onlookers.

"These are very useful skills... I am thankful to them," said Naina Rai, a 19-year-old who has been living in the camp for over a month.

"Living here is not like home, you are surrounded by strangers all the time. But now if a boy tries to tease me, he won't be safe," Rai told AFP.

Police official Thapa said more than 40 women and 80 children have attended the classes so far and plans were under way to extend the training to other camps as well.

Widespread unemployment, poverty and the impact of a 10-year Maoist insurgency have made Nepali women and children easy targets for traffickers, and campaigners say that the recent disaster has increased the threat.

Police and security agencies have increased vigilance against trafficking in quake-hit areas and along the Nepal-India border.

In an effort to prevent the trafficking of children, the government recently imposed a three-month ban on adoption and made it mandatory for travelling youngsters to carry permission letters if they are not accompanied by parents.

A 2013 report by the Himalayan nation's human rights commission recorded 29,000 incidences of trafficking or attempted trafficking in the country.