Leaked documents reveal New Year's Eve assaults far worse than initially reported; activist admits concealing she was raped by refugees.

More than half a year after a flury of rapes and sexual assaults across German cities last New Year's Eve shocked the country and sparked mass protests against the wave of refugees into Europe, leaked police documents reveal the number of incidents was even higher than initially reported.

Germany authorities initially denied claims that large numbers of refugees had sexually assaulted women at New Year's Eve gatherings across the country, but later conceded that "hundreds" of complaints of rape or other attacks were filed .

Even after German police acknowledged the sexual assaults, however, the number listed never reflected the true scale of the attacks.

While the number of such incidents was initially said to be in the low hundreds, later rising to some 500, a police document leaked to German news outlets on Tuesday placed the figure at more than 1,200.

The Sueddeutsche Zeitung newspaper reported that more than 2,000 individuals were involved in the attacks, but only 120 had been identified, and only four convicted.

Of those identified, most were newly-arrived foreign nationals.

The revelation comes just days after a left-wing German politician and advocate for refugees admitted that she had concealed the fact that she had been gang-raped by a group of migrants.

Selin Goren, a representative of the Solid movement, initially told police she was attacked by a group of German-speakers, concealing the ethnicity of her attackers to prevent sparking "more hatred against migrants in Germany," said Goren, claiming that the New Year's Eve attacks had given fodder to anti-immigration "racists".

Goren later returned to the police to alter her report, admitting that the three men who attacked her and forcibly performed sexual acts on her appeared to be of Middle Eastern origin.