A Syrian migrant offered his wife as payment to people smugglers then joined them in raping her daily during the family's crossing to Europe, it has been revealed.

The incident is just one of thousands of unreported cases of sexual assaults perpetrated against migrant women making their way to Europe.

The husband, who had run out of money to pay the smugglers in Bulgaria, put forward his 30-year-old wife to the smugglers in order to earn the family's crossing.

Refugees wait in a registration centre in Passau, Germany. Some migrant women (not pictured) are subjected to sexual assaults while living in vulnerable conditions at detention centres or during their trip to Europe

But he soon started joining the smugglers in the daily rapes, in what an expert described as a 'twisted logic' in which the man's wife had become the 'guilty party'.

According to the New York Times, the unidentified woman - a mother-of-four - now lives in Berlin with her children.

Although there is now a restraining order against her abusive husband, she is terrified of being killed by him for bringing 'dishonour' to their family.

Susanne Hohne, a psychotherapist in Berlin who treats female migrants, told the paper the woman displays signs of post traumatic stress disorder.

'One moment she will seem perfectly healthy, the next she is in her chair opposite you dodging bullets in Damascus or reliving her abuse in Bulgaria.'

However, she is not alone. Thousands of migrant women, often vulnerable and completely dependent on their husbands or male family members during their trek to Europe, face similar ordeals.

Last year four women's rights organisations co-signed a letter to Germany's Minister of Integration and Social Affairs in Hesse state described a culture of 'rape and violence' at asylum seeker shelters.

The letter, authored on August 18, stated: 'It is a fact that women and children are unprotected. This situation is opportune to those men who already regard women as their inferior and treat unaccompanied women as “fair game”.

'As a consequence, there are reports of numerous rapes, sexual assaults and increasingly of forced prostitution. These are not isolated incidents.'

Esraa al-Horani, a former makeup artist from Syria, told the New York Times she had dressed as a man and stopped washing to avoid being attacked.

Esraa al-Horani, a migrant from Syria, said she stopped washing and dressed as a man in order to ward of men's advances. She also claimed to sleep at her emergency shelter with a cupboard pushed against the door

She spends her nights in an emergency shelter in Berlin with a cupboard pushed up against the door.

Another, named only as Samar, described spending 14 months with her three daughters, aged 2, 8, and 13, on the trek from Syria to Berlin.

Refusing to let her daughters out of her sight, she and other female travellers banded together to take turns watching over the group while the others slept.

However, she too was propositioned by a people smuggler in Turkey - who offered to take her to Greece for free if she had sex with him.

She refused, but described hearing him wandering the halls of the hostel late at night.

She told the paper: 'Everybody knows there are two ways of paying the smugglers. With money or with your body.'

Meanwhile, the sexual violence continues to plague many of the refugee camps in Germany, where Chancellor Angela Merkel has pledged to take in hundreds of thousands of migrants.

This woman, named only as Samar, said she refused a smuggler's advances in Turkey when he offered to take her and her daughters to Greece for free if she slept with him

Johannes-Wilhelm Roerig, the federal commissioner for child sexual abuse issues, said: ‘I am most concerned that refugee children in camps, gymnasiums, or former barracks are not sufficiently protected from sexual assault.’

Other reports suggest migrant women in the refugee camps are being forced into €10-a-time prostitutes.

At one migrant centre in the town of Kitzingen, officials are now only employing male cleaning staff after a female employee was allegedly sexually assaulted every day for ten days.

Campaign group Women For Refugee Women has previously stated the solution is to integrate genuine refugees as quickly as possible into society to remove them from the risks of overcrowded conditions.