Unofficial Islamic schools, many of which use teachers who have not had criminal record bureau checks should be better regulated, an MP has demanded.
Madrasas are usually attached to a mosque, providing religious instruction in the evenings and at weekends.
But many are run unofficially in homes by imams and teachers without any qualifications or background checks.
Khalid Mahmood, MP for Perry Barr in Birmingham, said proper regulations were needed to protect children.
The Mosques and Imams' National Advisory Board said there were about 2,000 official madrasas in the UK that were known to their local councils and whose staff had undergone all the checks required to teach children in a safe and secure environment.
However it said it was very difficult to estimate the number of unregulated madrasas that were being held in people's homes.
Child protection laws
Mr Mahmood said: "Parents need to understand if they want to provide the best education for their children, then there has got to be proper regulations and proper systems in place.
"One of the biggest problems we have got is disaffection among young people from within our community, and it's because people are not qualified to teach.
"They're not embedded within our education system, and therefore they don't really get the teaching that's necessary for them."
Some parents have concerns about unregulated home schools.
Mourad a mother from Birmingham said: "I wouldn't send my kids there unless they've been CRB checked and I would really have to know more about the teacher."
One mother, who did not want to be named, said: "You do hear reports where some of them [madrasas] smack their kids, but I know the one I send them to doesn't do that."
The Muslim Council of Britain said there were three types of madrassa currently being run in the UK.
Tahir Alam, from the council, said: "The first one is a mosque-based madrasa, the second is where you'll get volunteers hiring out a community centre or school hall and are trying to impart their knowledge of Islam, and the third is the one you find on the road, in the front room of a house."
Like sports clubs, Scouts, Guides, and Christian Sunday schools, madrasas are not specifically regulated.
However, they are bound by child protection laws and laws relating to health and safety in voluntary sector organisations.
Manners and respect
BBC Asian Network approached an unregulated madrassa but the people running it refused to comment.
Meanwhile an official madrasa at the Jame Masjid Mosque in Birmingham has seens its roll decline. Spokeman Ahmed Qazi, spokesman for the Jame Masjid Mosque in Birmingham, said it was often because often it was more convenient for parents to send their children to an unofficial madrasa.
Mr Qazi said: "The excuses that parents come out with are very petty. They say, "oh it's a couple of doors down the road, its easier for the wife to collect the kids".
"The mosque is a long walk and the weather is very bad sometimes, and because these madrassas are nearby, the children can go on their own."
Fatima Ramji is the principal of the Muhammadi Madrassa in Birmingham, a regulated school which operates on Sunday mornings for children aged between five and 16.
She said it was important for children to learn at a fully regulated madrasa, as it provided a higher standard of religious education.
"They will learn about the Koran, about history and we teach them manners and how to behave in wider society.
"We teach them to respect elders and teachers, plus the older children will be learning how to build their characters, and we also have a drugs awareness programme."
However anybody working with children in the UK will have to register with the Independent Safeguarding Authority from next July.
It has been set up to prevent unsuitable people from working with children and vulnerable adults, and covers all those working in the voluntary sector.
But the question remains whether those teaching from home will willingly sign up to the system.
This article first appeared on BBC Asian Network on 14th October 2009.