A female asylum seeker helper working in a Hamburg refugee registration centre is poised to quit because of cheating, death threats and demands for a luxury life from the migrants.

In a searing indictment of the behaviour of the refugees, the unnamed woman said her idealism had been eroded and virtually destroyed.

At first she was enthusiastic and wanted to help out with processing the tens of thousands of migrants arriving in Germany on a weekly basis when they first began to arrive.

The unnamed woman from Hamburg, Germany, claims her idealism had been eroded and virtually destroyed after working with the refugees. Pictured are a group of migrants making their way through Slovenia in October

Now, she told the Welt am sonntag newspaper, she is disillusioned, disheartened and on the verge of quitting as the situation deteriorates.

Describing how she applied for the job because it was 'exactly' what she wanted to do, she said her enthusiasm drained away in the first few days.

She has worked at the centre since autumn 2015 and the newspaper said it had her identity - but would not reveal it at her request.

'Many of them are extremely demanding,' she explained. 'They come to me and ask to get an apartment and a fancy car and, best of all, even a really good job for them.

'If I try to explain to them that's not possible, they are often noisy or even really aggressive.'

The woman said a group of Syrians and Afghans once said they would go on hunger strike unless she helped them move elsewhere.

One Arab man even yelled at a colleague: 'We decapitate you!', she claimed.

But what she considered as 'the worst' of their behaviour was their treatment of women, saying many of the male refugees did not take her seriously.

Instead, they would simply dismiss what she would tell them and contact her male colleagues.

'For us women they have often only scornful looks - or just intrusive,' she added. 'They whistle loudly, say something to one another in a foreign language, laugh.'

Migrants sleep wrapped in blankets inside a registration camp in Presevo, Serbia, amid plummeting temperatures

She said there had been occasions when the refugees had taken photographs of the women without asking their permission first.

She also said she has gone from wearing close-fitting clothes to 'wide-cut trousers' and tops with high necklines.

The woman said that not all the refugees are the same. She explained many are friendly and grateful, but 'working with 90 per cent of them is rather awkward'.

Meanwhile, German authorities said Monday that nearly all the suspects in a rash of New Year's Eve violence against women in Cologne were 'of foreign origin' as foreigners came under attack amid surging tensions.

Ralf Jaeger, the interior minister of North Rhine-Westphalia state, released initial findings of a criminal probe over the crime spree that has piled pressure on Chancellor Angela Merkel over her liberal stance towards refugees.

'Witness accounts and the report by the [local] police as well as findings by the federal police indicate that nearly all the people who committed these crimes were of foreign origin,' he said.

Although no formal charges have been laid, Jaeger said the attackers emerged from a group of more than 1,000 'Arab and North African' men who gathered between the main railway station and the city's iconic Gothic cathedral during the year-end festivities.

But reports they were responsible have led to a rash of racially targeted reprisals.

Police said a mob attacked a group of six Pakistanis late Sunday in Cologne, two of whom had to be hospitalised.

Shortly afterwards, five unidentified assailants attacked a 39-year-old Syrian national, injuring him slightly.