Just a few miles from Israel's border, a cruel but lucrative business in kidnap and ransom is growing, according to separate reports just released by two Israeli charities.

Since 2005 more than 35,000 illegal African immigrants have reached Israel via Egypt, most with the help of paid Bedouin traffickers who helped those who approached them in return for an agreed fee.

But in early 2010 the traffickers began picking up Eritrean asylum seekers, whether or not they wanted to be taken anywhere, and transporting through the Sinai towards the Israeli border, according to reports by Physicians for Human Rights-Israel (PHR) and Hotline for Migrant Workers.

The charities, both basing their evidence on interviews conducted with asylum seekers they are helping, reported that the traffickers hold the Eritreans to ransom in cruel and violent conditions, extracting money from friends or relations abroad before agreeing to release them.

More than 86 women told PHR that they had been raped, the organisation revealed. Some 59 per cent of the trafficked individuals it interviewed were held under guard or shackled to each other, and 52 per cent were subjected to physical abuse.

The Hotline for Migrant Workers received testimonies saying that, in some cases, the traffickers have used people as construction slaves. It found that in December people were being held for an average of three months.