KABUL (Reuters) - Almost 30 years of conflict have forced millions of Afghan children to go without education and work to help feed their families, UN and Afghan government figures released on Wednesday showed. Of Afghanistans 8.4m children - more than a third of the population of 28m - 1.2m are the main breadwinners for their families and many more supplement family incomes, according to a survey conducted by the Afghan government, UNICEF and the independent Afghanistan Research And Evaluation Unit (AREU) from 2008 to 2009. There are some 6.5m children at risk in Afghanistan who are deprived of education, Wasel Noor Momand, Afghanistans deputy minister of public work and social affairs, told a news conference in Kabul. Child labour is one of the major issues in Afghanistan that we have to eliminate, he said. Momand said poverty, poor security, lack of education and an influx of refugees returning to Afghanistan from neighbouring countries are the main factors that compel families to force their children to work. The survey was conducted in three of Afghanistans most populated provinces: Kabul, Badakhshan and Herat. It showed children were employed in a range of light and heavy jobs from washing cars in the street to working in shops and restaurants as well as in mechanical workshops and factories. About a quarter of child labourers are girls who usually work as housekeepers to support their families, the survey said. Afghanistan is one of the poorest and most underdeveloped countries in the world. Most Afghans live on an estimated $2 a day and unemployment is at 40 per cent. Afghan employment law stipulates that children can work from the age of 15 but their working hours must not exceed 35 hours a week. Momand said some children under 15 are employed in heavy labour for more than 40 hours a week. AREUs Afghanistan director, Paula Kantor, said education and public awareness about childrens rights play an important role in preventing families and communities from using their children in the workforce. Security in Afghanistan has deteriorated since Taliban insurgents made a strong comeback in 2006, with attacks across the country making it difficult for many to work freely and even forcing some in remote areas to join the Taliban for income.