A German region has reported a spike in sex attacks last year by 'non German' men at swimming pools a week after the country's most populated region, North Rhine-Westphalia, blamed immigrants for the rising tide of assaults.

Police in Lower Saxony reported that 'sporadic group sexual assaults' have been reported in what they call a 'new phenomenon.'

'On occasion crimes have been registered in which the perpetrators have have acted from within larger groups,' according to one official.

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The migrant was jumping from the diving board at Theresienbad pool (pictured above) when police came to arrest him with the man now sentenced to six years jail

'This type of crime is notable because sexual crimes are usually almost exclusively committed by people acting alone. It is a new form of criminality.'

On Thursday last week German lawmakers moved to seal up holes in Germany's rape laws in a measure dubbed 'No Means No.'

From now on, people connected with a mob sex attack face being punished as rapists even if they personally committed no crime.

The new law was rushed through parliament following the mass sexual frenzy in the city of Cologne on New Year's Eve when mobs of immigrant men robbed and assaulted hundreds of women in the chaos of the celebrations.

Last week in a secret police report detailing escalating sex crimes by immigrants at public swimming baths across Germany was leaked in Dusseldorf where its authenticity was confirmed by authorities.

The internal report was issued for officers of the Criminal Commisariat 12 - responsible for sex crimes and missing persons - and stated: 'The K12 can confirm a surge in sex crimes at these establishments.

'In particular rape and the sexual abuse of children in bathing establishments have given us grave cauve for concern. The perpetrators are, for the most part, immigrants.'

Last month an Iraqi migrant (pictured, centre) was jailed for six years for raping a 10-year-old boy in a swimming pool in Vienna

But while the Lower Saxony reported chronicled a rise in sex assaults last year and the first quarter of 2016, for the past three months there have been no attacks at public pools in the state.

Police believe members of the public are more prepared to report sexual assaults and would-be offenders are thinking twice before preying on women and children.

'So far in 2016 a majority of suspects were non-German whereas in previous years a clear majority were German', police said.

In North Rhine-Westphalia, the state in which both Cologne and Dusseldorf lie, a total of 103 sex crimes have been reported at pools across since the beginning of this year.

'The allegations range from insults to exhibitionism to assault and rape,' said a local authority spokesman, adding that a 'disproportionate' number of allegations were made against men with a migrant background.

Out of control: Footage of New Year's Eve in Cologne shows the celebrations going terribly wrong as police try to control the huge crowds of revellers where hundreds of women were sexually abused

In 2014, there were seven cases of sex crimes reported at swimming pools in Duesseldorf, with an increase to 17 in 2015. This year police in the state capital have received eight allegations of sex crimes at local baths.

One 20-year-old Syrian man is facing trial in the coming weeks after he grabbed and kissed the arm of a 14-year-old.

In January, one NRW swimming pool in Bornheim banned male refugees after swimmers said they felt threatened by their presence. Pool 'etiquette courses' were then initiated and the ban lifted after five days.